- How traditional purchasing works and when it is the right procurement route
- What dynamic purchasing systems are and how they differ from conventional approaches
- The key differences in supplier access, flexibility, and the tender process
- How dynamic purchasing systems compare to framework agreements
- When each method is the right choice for a contracting authority
- How to manage both procurement routes efficiently with the right tools
Public sector procurement is not a single approach — it is a collection of routes, each designed for a different set of circumstances. For contracting authorities, choosing the right method directly affects how quickly requirements can be met, how competitive the supplier market is, and how defensible the award decision will be. For suppliers, understanding how each route works is equally important: it determines how to access opportunities and what the bidding process will look like, especially as more organisations move from traditional non-digital procurement methods to eSourcing platforms. Dynamic purchasing systems are one of the most significant developments in UK public sector procurement in recent years, with the volume of contracts referencing them increasing by 125% between 2018 and 2023. Yet many buyers and suppliers still conflate them with traditional purchasing routes or framework agreements. This guide explains the key differences clearly.
Why the Way You Buy Matters in Public Procurement
Every procurement decision involves a trade-off. Contracting authorities must balance speed against rigour, compliance against flexibility, and access to the best possible suppliers against the practicalities of running a procurement process. The procurement vehicle chosen at the outset shapes all of those outcomes — it determines who can bid, how quickly a contract can be awarded, and what obligations the authority takes on throughout the process. The chosen route also determines the award criteria used to evaluate and score bids, which is essential for ensuring compliance and value.
Historically, most public sector buying followed a relatively fixed pattern: advertise, qualify, evaluate, award. That approach remains valid for many requirements. However, as public sector spending on goods and services continues to grow — reaching £434 billion in 2024/25 according to Cabinet Office data published in July 2025 — there is increasing pressure to find routes that are both more efficient and more accessible to a wider range of suppliers. Dynamic purchasing systems have emerged as one of the most practical answers to that challenge, and the Procurement Act 2023 has further expanded their potential scope.
Explore how Delta eSourcing supports both traditional and DPS procurement — visit delta-esourcing.com.
What Is Traditional Purchasing? A Quick Overview
Traditional purchasing in UK public procurement refers to the established competitive tendering routes that have defined the sector for decades. In practice, this typically means an open or restricted procedure: a contracting authority publishes a contract notice, invites suppliers to submit expressions of interest or full tenders within a fixed window, evaluates responses against defined criteria, and awards a contract to the highest-scoring compliant bid. In traditional tender evaluations, price and quality are typically the most important criteria, as they determine both the competitiveness and value of the bid.
Suppliers must ensure their documentation and certifications are complete and current to demonstrate compliance and readiness for the procurement process.
The tender process under traditional purchasing is structured and sequential. Each stage has defined timescales — minimum notice periods, evaluation windows, and mandatory standstill periods between award decision and contract signature. That structure provides legal certainty and a clear audit trail, but it also means that traditional purchasing can be slow, particularly for requirements that arise frequently or in fast-moving markets.
Traditional purchasing also tends to be relatively closed at the point of competition. Once the notice period closes, the supplier pool is fixed. Any business that missed the advertisement window — or did not meet the qualification criteria at that point in time — has no way to participate in that particular procurement.
What Are Dynamic Purchasing Systems?
A dynamic purchasing system (DPS) is an open, fully electronic procurement process through which any supplier meeting the qualification criteria can apply to join at any time during its lifetime. Unlike a traditional procurement, a DPS does not close its doors after the initial competition — the market remains permanently open, and suppliers can join or leave throughout the system’s life.
Under the previous Public Contracts Regulations 2015 (PCR 2015), dynamic purchasing systems were restricted to commonly used goods and services that were generally available on the open market. The Procurement Act 2023, which came into force on 24 February 2025, significantly expanded this: its replacement for DPS — now called a “Dynamic Market” — can be established for any type of goods, services, or works, not just commodity purchases. For practical purposes, the core concept is the same: a continuously open list of pre-qualified suppliers, from which buyers run mini-competitions to award individual contracts. While framework agreements are often established by central government or other collective contracting authorities, DPS is designed to provide equal opportunity and free access to all qualified suppliers throughout its lifetime.
Each time a contracting authority needs to make a purchase, it runs a mini-competition among the suppliers on the system. This is not optional — unlike framework agreements, dynamic purchasing systems do not permit direct awards. Every contract must be awarded competitively.
Key Differences Between Traditional Purchasing and Dynamic Purchasing Systems
Supplier Access and Open-Market Competition
The most fundamental difference between traditional purchasing and a DPS is how the supplier market is treated. Traditional purchasing creates a closed competition: once the tender window closes, only those suppliers that responded can be considered. Businesses that were not ready, not aware of the opportunity, or did not exist at the time of the notice are simply excluded.
A DPS operates as an open-market system throughout its life. Any supplier that meets the qualification criteria can apply to join at any time. However, while a DPS is open to all qualified suppliers, actual participation may still depend on the supplier’s available funds, income, and assets, which can affect their ability to compete effectively. As a result, the pool of potential suppliers is continuously refreshed — newer businesses, specialist firms, and smaller businesses that might not have been in the market when the DPS was first established can still participate. This open-market model is one of the primary reasons dynamic purchasing systems have become popular for requirements in fast-moving sectors such as technology, staffing, and construction.
Flexibility and Speed of Procurement
Traditional purchasing timescales are largely fixed by regulation. An open procedure, for example, requires a minimum tender period of 25 days under the Procurement Act 2023. Factoring in publication, evaluation, standstill, and award, a traditional procurement for even a relatively straightforward requirement can take several months from start to contract signature.
A DPS offers significantly more agility once it has been established. Because suppliers are already pre-qualified, individual mini-competitions can focus purely on the specific requirement. Simple procurements can be initiated in as little as 10 days, according to Crown Commercial Service guidance, especially when supported by a dedicated Dynamic Purchasing System (DPS) module. This makes DPS particularly well-suited to high-volume, recurring purchases where the overhead of a full traditional procurement for each requirement would be disproportionate. DPS is especially effective in markets where demand fluctuates, requiring suppliers to adopt sustainable pricing strategies to remain competitive over time.
Supplier Onboarding — Fixed vs. Rolling Admission
Under traditional purchasing and closed framework agreements, the supplier list is fixed at the point of award. If a business was not successful at the qualification stage, or was not operating at the time, it has no route into that particular vehicle until it expires and is re-tendered.
Dynamic purchasing systems work differently. Admission is rolling — suppliers can apply to join at any point during the system’s lifetime, and there is no cap on the number of suppliers that can participate. Companies seeking to join a DPS must demonstrate financial stability, as this is a key factor in ensuring the reliability and capability of the supplier pool. This means a DPS does not become outdated in the same way that a fixed framework can. The supply base naturally evolves as new entrants join and inactive suppliers exit, keeping the market competitive and current.
How Call-Offs and Direct Awards Differ
Framework agreements allow contracting authorities to award call-off contracts either through mini-competitions or, in certain circumstances, through direct awards to a named supplier on the framework. This flexibility is one of the reasons frameworks remain popular for straightforward, well-defined requirements. In some cases, a single supplier framework may be established, or a contract may be awarded to only one supplier, particularly where intellectual property rights or security considerations justify such an approach.
Dynamic purchasing systems do not permit direct awards under any circumstances. Every contract under a DPS must be awarded through a mini-competition among the relevant qualified suppliers. This requirement ensures that competition is maintained at every stage, which supports value for money and legal defensibility — but it does mean that DPS is not suited to situations where a contracting authority needs to move exceptionally quickly to a single named supplier.
How the Tender Process Differs Between the Two Approaches
The tender process looks substantially different depending on the procurement route chosen, and it is increasingly being managed through end-to-end eProcurement systems.
Under traditional purchasing, the sequence is: publish contract notice → qualification stage (if restricted procedure) → issue tender documents → receive and evaluate responses → notify award decision → observe standstill period → sign contract. The contract award process includes formal communication with suppliers and the publication of a contract award notice, which is essential for transparency. Each step is prescribed, and the process must be completed in full for each new requirement.
Under a DPS, the process has two distinct phases. First, the system itself is established — the contracting authority publishes a notice, sets qualification criteria, admits suppliers, and opens the market. This is a one-time investment. Thereafter, for each individual requirement, the authority runs a mini-competition: issue invitation to tender to relevant suppliers → receive responses → evaluate → award. Clear communication and effective management are crucial to ensure suppliers can deliver on their commitments following a successful mini-competition. There is no need to re-advertise from scratch, and no need to re-qualify suppliers already admitted.
| Stage | Traditional Purchasing | Dynamic Purchasing System |
|---|---|---|
| Market opening | Per procurement | Once (at system establishment) |
| Supplier qualification | Per procurement | On admission to the system |
| Tender process | Full process each time | Mini-competition per requirement |
| Direct awards | Permitted (framework) | Not permitted |
| New suppliers joining | Not possible mid-process | At any time |
| Typical timeline | Several months per procurement | As little as 10 days per mini-competition |
Framework Agreements vs. Dynamic Purchasing Systems — Are They the Same?
Framework agreements and dynamic purchasing systems are often conflated, but they are distinct tools with important differences. Understanding those differences matters for both contracting authorities selecting a procurement route and suppliers deciding where to focus their qualification efforts.
A framework agreement is established through a competitive process and results in a fixed list of approved suppliers. Once the framework is awarded, it is closed — no new suppliers can join, regardless of how good they are or how much the market has changed. Traditional frameworks run for up to four years; the Procurement Act 2023 also introduced “open frameworks,” which can run for up to eight years and allow new suppliers to join at defined points during their life, particularly when supported by enhanced digital procurement processes.
A dynamic purchasing system (or dynamic market under the Procurement Act 2023) remains open throughout its lifetime. There is no fixed end date, no cap on supplier numbers, and no exclusion for businesses that were not ready or did not exist when the system was first established. Every contract must be awarded by mini-competition — direct awards are not available.
In short: frameworks offer more flexibility in how individual contracts are awarded, including direct award options, but they lock in a supplier pool. Dynamic purchasing systems maintain a continuously competitive and accessible open market, but require a mini-competition every time.
When Should a Contracting Authority Use a DPS Over Traditional Purchasing?
The choice between a DPS and traditional purchasing depends on the nature of the requirement, the market, and how often the contracting authority expects to buy.
Dynamic purchasing systems are well-suited to high-volume, recurring purchases in markets with many potential suppliers — for example, temporary staffing, construction and maintenance works, IT commodities, and professional services where the supply base is fragmented and constantly evolving. DPS is also effective for development projects and research activities conducted at the request of various agencies, supporting early-stage design, testing, and innovation. In these contexts, establishing a DPS once and running repeated mini-competitions is far more efficient than running a full traditional procurement each time, especially when using a comprehensive public sector eSourcing platform to manage activity.
Traditional purchasing remains the right choice for complex, one-off, or highly bespoke requirements where the contracting authority needs to engage deeply with the market, set tailored evaluation criteria, and potentially negotiate the final terms. Large infrastructure projects, technology implementations with significant integration requirements, or contracts where the specification cannot be defined in advance typically call for a full traditional tendering process.
When selecting the most appropriate procurement method, contracting authorities must consider the best interests of the individuals or organizations they serve, ensuring that the chosen route delivers the greatest overall benefit.
The Procurement Act 2023 has widened the use case for dynamic markets beyond the previous restrictions on DPS, meaning contracting authorities now have more freedom than before to apply this approach across a broader range of categories.
Benefits and Limitations of Each Approach
Advantages of Dynamic Purchasing Systems
Dynamic purchasing systems offer several practical advantages, particularly for contracting authorities managing recurring requirements. The continuously open market means the supply base stays current and competitive. New entrants — including smaller businesses and specialist firms — can join at any point, which improves access and promotes innovation. Mini-competitions are faster than full traditional procurements, reducing the administrative burden for both buyers and suppliers over time, especially when supported by integrated eProcurement software solutions. For smaller businesses especially, the lower barrier to initial admission makes DPS a more accessible entry point into public sector work than a closed framework.
Advantages of Traditional Purchasing Routes
Traditional purchasing methods retain clear advantages for certain requirements. They give contracting authorities precise control over who participates and how the evaluation is structured — important for complex or high-value procurements where getting the right supplier matters more than speed. The legal frameworks governing traditional procedures are well-established and well-understood, which reduces compliance risk, particularly when combined with robust procurement, contract and tender management tools. For one-off requirements that are unlikely to recur, the overhead of establishing a DPS makes traditional tendering the more proportionate choice.
Limitations to Consider for Both
Neither approach is without drawbacks. Dynamic purchasing systems require upfront investment to design, establish, and manage the system and its admission process — and contracting authorities must run a mini-competition for every contract, which adds process overhead compared to a direct award from a framework. Traditional purchasing, meanwhile, can be slow and expensive relative to its benefit for straightforward recurring requirements, and the fixed tender window can exclude capable suppliers who were not in a position to bid at that specific point in time.
Common Questions About Dynamic Purchasing Systems and Traditional Procurement
What is the difference between a DPS and a framework agreement?
A framework agreement creates a fixed list of approved suppliers that is closed after award. A dynamic purchasing system remains open to new suppliers throughout its lifetime and requires a mini-competition for every contract — direct awards are not permitted. The Procurement Act 2023 renamed DPS as “Dynamic Markets” and expanded their scope, while also introducing “open frameworks” as a middle ground that allows some supplier admission during the framework’s life.
Can SMEs join a dynamic purchasing system?
Yes — and this is one of the key advantages of the DPS model. The initial admission assessment for a DPS is typically less intensive than the qualification stage for a closed framework, making it more accessible for smaller businesses. The Government has set a target of directing 22% of procurement expenditure to SMEs by the end of the 2027/28 financial year, and dynamic purchasing systems are one of the tools being used to support that goal.
How long can a dynamic purchasing system run?
Under the previous Public Contracts Regulations 2015, dynamic purchasing systems had no maximum duration. The Procurement Act 2023’s “Dynamic Markets” carry this forward — there is no set time limit, and the system can remain open as long as the contracting authority has ongoing needs. Traditional framework agreements are generally limited to four years, though the new “open frameworks” introduced by the Act can run for up to eight years.
Are direct awards allowed under a DPS?
No. Every contract awarded through a dynamic purchasing system must go through a mini-competition among the relevant qualified suppliers on the system. This is one of the key distinctions between DPS and framework agreements, which do permit direct awards in certain circumstances.
What types of contracts are best suited to a DPS?
Dynamic purchasing systems work best for high-volume, recurring purchases where the supply market is broad and evolving — such as temporary staffing, construction and maintenance, IT commodities, and professional services. They are less suited to one-off, complex, or highly bespoke requirements where a traditional competitive tender is more appropriate.
Managing Traditional and DPS Procurement Efficiently With Delta eSourcing
Whether your organisation runs traditional competitive tenders, operates a dynamic purchasing system, or uses both depending on the requirement, the underlying challenge is the same: managing the process efficiently, keeping documentation compliant, and ensuring that every award decision is properly evidenced — often by working with an experienced eSourcing provider like Delta eSourcing.
Delta eSourcing is designed to support the full range of public sector procurement routes — from publishing contract notices and managing the tender process for traditional procurements, to managing supplier admission, running mini-competitions, and maintaining audit trails for DPS activity. Having both capabilities in one platform reduces the administrative overhead of switching between tools and helps procurement teams maintain consistent standards regardless of which route a particular requirement calls for, while buyers can also build capability through specialist procurement events and training and focused public sector procurement webinars.
Whether you are running a DPS or a traditional tender, Delta eSourcing makes procurement simpler — get started at Delta Esourcing.