How to Size Your Addressable Public Sector Market

The UK public sector spends approximately £300 billion a year with private sector suppliers. That figure is publicly available, but it is not enough to base a market entry or growth decision on. The question most commercial teams are actually asking is narrower: how much does government spend on what we sell, with which buyers, and through which routes to market? This guide explains how to answer that question, using published contract data, CPV codes, and Tussell's spend analysis tools.

Skip ahead to read about:

• How UK public sector contract data is published
• How to use CPV codes to size your market
• How to find the amount of spending in your sector
• Free market sizing resources by sector
• How to size the UK public sector market using Tussell
  
  

How is UK public sector contract data published?

UK public sector contract data is published across several official portals. Find a Tender is the central platform for regulated procurement notices in England and for relevant procurements elsewhere in the UK, while Scotland, Wales and Northern Ireland also use dedicated services including Public Contracts Scotland, Sell2Wales and eTendersNI. Buyers may also use their own tender portals and procurement platforms.

In practice, this means a large body of UK public sector contract data is publicly available and structured. It covers the contracting authority, the supplier, the value, the contract duration and - crucially - a classification code. That classification code is where market sizing starts.

How to use CPV codes to size your public sector market

Public sector contract notices include at least one CPV code - Common Procurement Vocabulary - used to classify what is being procured.

CPV codes are useful for market sizing, but they are imperfect. Codes can be applied inconsistently, contracts may carry several codes, and newer categories such as AI may not have a dedicated code at all. Large bundled contracts can also cover several different products or services.

For that reason, the best approach is to combine multiple relevant CPV codes with keywords to identify contracts in your service line. Keywords have their own limitations: too broad, and you risk overstating the market; too narrow, and you risk missing relevant contracts, particularly where notices use generic or inconsistent language.

It is also important to remember that CPV codes classify contract awards, not actual spend. They can help you estimate the value of contracts awarded in a market over a given period, but award values can fluctuate significantly year to year and may not reflect how much buyers actually spend annually.

For niche markets, accurate market sizing therefore means mapping the right CPV codes and keywords, then interpreting the resulting contract values carefully. For larger markets crossing numerous service lines, another - more accurate approach - can be taken.

How to find the amount of spending in your sector

For broad sectors such as IT or facilities management, invoice-level spending data is often more useful than contract award data. Rather than adding up the value of contracts awarded in a given year, you can look at how much relevant public sector buyers have actually paid to suppliers operating in that sector.

One approach is to identify suppliers using relevant SIC codes, then aggregate the invoices paid to those suppliers. This gives a better indication of annual market spend than contract award values, which can be distorted by large multi-year contracts. It also allows much more granular analysis - for example, estimating how much a specific council, NHS trust or government department spends in your market.

Invoice data is not published through tender portals such as Find a Tender, so accessing and analysing it usually requires a dedicated public sector market intelligence platform such as Tussell, which brings invoice and contract data together in one place.

SIC codes have limitations too: they describe the supplier rather than the specific purchase, and some large suppliers may operate across several markets. They are therefore best used alongside supplier-level and transaction-level checks.

Free market sizing resources by sector

Invoice-level analysis and contract award data can both help you size a public sector market. But if you do not have access to a market intelligence platform, Tussell also publishes free research covering a range of major sectors.

Technology and IT services. Tussell’s Tech Titans report analyses the UK public sector technology market, including the highest-earning suppliers, major buyers and how the market is changing over time.

Artificial intelligence. AI is difficult to size using CPV codes alone because there is no dedicated AI classification. Tussell’s research uses a broader methodology to identify relevant contracts and track how public sector demand for AI is developing.

Defence. Defence procurement is a large and complex market, with activity spread across major programmes, frameworks and a wide supplier base. Tussell’s defence research brings together available procurement data to show where opportunities and spending are concentrated.

Facilities management. Tussell’s FM Market Snapshot sizes the public sector facilities management market and identifies the suppliers and buyers shaping it.

AEC consulting. Tussell’s AEC Consulting Market Snapshot looks at public sector spending across architecture, engineering and construction consulting, including the major buyers and suppliers.

Management consulting. Tussell’s Management Consulting Market Snapshot provides a view of the size and structure of the public sector consulting market, including where spend is concentrated and which suppliers are winning work.

Other sectors. Explore Tussell’s reports for market analysis across a wider range of public sector categories. Or, book a chat with the team to see how Tussell’s market intelligence platform can help you size your market and build pipeline.

How to size the UK public sector market using Tussell

Tussell brings together, cleans and augments public sector contract and spending data from across the UK. This removes much of the time, cost, and risk of error involved in sourcing, cleaning and reconciling fragmented public procurement data yourself - giving you a more reliable foundation for sizing your market.

Define your market. Combine categories, CPV codes, keywords, suppliers and other filters to identify the part of the public sector market that is relevant to you.

See where the money goes. Use invoice-level spending data to understand how much individual buyers - from government departments to councils and NHS organisations - spend with your competitors or suppliers in your market.

Understand the supplier landscape. See which suppliers receive the most public sector revenue, which buyers they work with and where competition is concentrated. If your route to market involves larger primes, you can also identify potential Tier 1 partners active in your market.

Analyse contract awards. Explore the value of contracts awarded, who won them, which buyers awarded them, the routes to market used, and the value and volume of relevant contract expiries and upcoming opportunities.

Size framework opportunities. Understand the scale of individual frameworks and Lots, which buyers use them, which suppliers are winning through them and where relevant opportunities are concentrated.

Track the market over time. Compare spending and contract activity across different periods to understand whether a market is growing, shrinking or shifting between buyers and suppliers.

The result is not just a market-size figure. It gives you a clearer view of which buyers to target, who you are competing with, which partners matter, which frameworks and Lots are most relevant, and where future opportunities will come from - helping you build pipeline and target the right accounts more effectively.

Frequently asked questions

How do I size my public sector market?

There is no single method that works for every market. For narrower categories, start by combining relevant CPV codes with keywords to identify matching contract awards. For broader sectors, invoice-level spending data can give a better indication of how much public sector buyers actually spend with relevant suppliers.

Public procurement data is spread across multiple national and buyer-specific sources, while invoice data sits outside the main tender portals. Tussell brings this data together, cleans and augments it, and lets you analyse your market by buyer, supplier, category, framework and time period - without having to source and reconcile the underlying data yourself.

How do I calculate total addressable market in the UK public sector?

Your total addressable market (TAM) is the total value of relevant public sector demand for the goods or services you sell across central government, local authorities, the NHS, devolved nations and other public bodies.

The right methodology depends on the market. For broad sectors, invoice-level spending data is often the best starting point because it shows how much relevant buyers actually spend with suppliers in that market. For narrower categories, contract award data filtered using a combination of CPV codes and keywords can help estimate the value of relevant opportunities being awarded.

Tussell brings these datasets together across the UK public sector, allowing you to define your market, size it consistently and break it down by buyer, supplier, framework and time period.

What are CPV codes and how do I use them for market sizing?

CPV codes (Common Procurement Vocabulary) are the standardised classification system used to categorise public sector contracts. Contract award notices include at least one CPV code describing what was procured.

They are useful for market sizing, but they have limitations. Codes can be applied inconsistently, contracts may include several codes, and newer categories such as AI may not have a dedicated code at all. For that reason, the best approach is usually to combine multiple relevant CPV codes with carefully chosen keywords.

CPV codes help you identify relevant contract awards, rather than actual spend. Tussell’s CPV code guide explains how the system works and how to identify the codes most relevant to your market.

How accurate is public sector contract data for market sizing?

Published contract award data covers contracted spend, not actual expenditure, and has two known gaps: framework call-off contracts below individual publication thresholds, and below-threshold awards that are not required to be published. In most categories, this means published data understates the true total by some margin. For market sizing purposes, published award data gives you a reliable floor and a consistent basis for comparison between buyers, suppliers, and time periods - even if it does not capture every pound of spend.

Conclusion

Sizing the UK public sector market is possible, but the right method depends on what you are trying to measure. Contract award data can help you understand the value and structure of opportunities in your market, while invoice-level data gives a clearer picture of how much buyers actually spend.

The challenge is bringing together fragmented sources, choosing the right CPV codes and keywords, and interpreting the data consistently. Tussell brings together, cleans and augments this data to make market sizing faster, more reliable and easier to turn into pipeline.

If you want a starting point, Tussell also publishes free market research across technology, AI, defence, facilities management, consulting and other major public sector markets.

Related: What are CPV codes?