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The War on Bid Rigging – Efforts to curb anti-competitive conduct in public procurement

Public sector spending on goods and services from the private sector has increased year on year for over a decade. Having spent around £245 billion in 2014-15, government accounts for 2024-25[1] show that £395 billion was spent on procurement, representing around one third of all public spending.

However, bid rigging continues to pose a significant concern in public procurement, undermining competition and inflating prices. Recent analysis by the Competition and Markets Authority (CMA) suggests that the ultimate cost to the UK taxpayer could be as much as £3.5 billion per year, with bid rigging in public contracts potentially increasing prices by 20% or more.

It is little surprise, therefore, that the CMA has made clear that cracking down on bid rigging is a strategic priority, including by engaging with the Ministry of Defence and other government departments to centralise data and reduce bid-rigging in their supply chains.

This blog will consider the extent of the problem posed by bid-rigging, what the CMA is doing to combat it, and how private enforcement can assist in parallel.

The extent of the problem

Bid rigging is, by its very nature, secretive and, consequently, difficult to detect. It can take many forms, including:

  • Cover bidding – competitors submit deliberately high or uncompetitive bids to create the illusion of competition.
  • Bid suppression – certain firms agree not to bid, or to withdraw bids, so that one of the conspirators wins.
  • Bid rotation – conspirators take turns winning contracts, dividing the market between them.
  • Market allocation – firms agree territorial or customer carve‑ups and do not genuinely compete.

Government analysis of public procurement has also shown that bid-rigging is pervasive across the sector, that it is not only limited to high-value tenders, and that it results in a very real cost to taxpayers and public services. Collusion can also weaken incentives to improve quality, delivery and innovation, disadvantages fair dealing suppliers, and can damage confidence in procurement institutions.

The CMA’s strategic focus

The CMA’s Annual Plan for 2026-2027 outlines its strategic objectives for 2026-2029 and specifically notes that it will prioritise enforcement activity relating to public procurement.

Key elements of the CMA’s approach include:

  • Targeted enforcement where collusion drives up prices for public bodies and taxpayers;
  • Making use of AI and other data science tools to scan bidding data and identify illegal activity at scale;
  • Continuing to use intelligence from public authorities, whistleblowers and leniency applications to detect bid‑rigging schemes.
  • Supporting deterrence through high‑profile investigations and sanctions, including fines, director disqualification, and entry in a central debarment register (under the Procurement Act 2023, cartelists now face potential inclusion in a central debarment register, and exclusion from future public tenders for up to 5 years).

The CMA is already making use of its AI and data science tools and reports that it is using an in-house tool to scan tender information at scale and look for suspicious patterns. The tool is in use in pilots with the Department for Work and Pensions, the Department for Education and the Ministry of Justice, and the CMA has said this approach is already generating enforcement leads. The CMA is now looking to extend that pilot to the Ministry of Defence as it seeks to centralise the collection of government procurement data in order to reduce manipulation in public contracts. [2]

Public and private enforcement

Public enforcement by the CMA remains the primary tool for tackling bid‑rigging:

  • The CMA can utilise its extensive investigative powers, impose significant fines, and secure director disqualification orders;
  • Criminal enforcement remains available in respect of the cartel offence – where certain criteria are met, an individual can be found guilty of a criminal offence, resulting in up to 5 years in prison and/or an unlimited fine (see CMA9, Cartel Offence Prosecution Guidance);
  • Leniency policies allow cartel members to come forward, providing crucial evidence.

However, public enforcement has inherent limits:

  • The CMA must prioritise cases based on resources and impact, so not every suspected infringement will be pursued; and
  • Even where the CMA sanctions wrongdoing, victims – including central government, local authorities, NHS bodies and other public entities – may still be left out of pocket.

Private enforcement can assist in parallel and help to address some of these limitations. In particular, victims of bid‑rigging can bring damages actions, including follow‑on claims based on CMA decisions and standalone claims with their own evidence base, in order to:

  • Recover overcharges paid as a result of collusive bidding, returning funds to public budgets;
  • Provide redress for wider impacts, such as increased operating costs or delayed projects; and
  • Enhance deterrence by increasing the expected cost of cartel participation beyond regulatory sanctions.

Comment

Bid‑rigging in UK public procurement is neither rare nor marginal; the evidence shows that it is systemic and it has a direct and substantial economic impact.

Even on the most conservative of estimates in the CMA’s analysis, bid rigging can result in overspend of £1 billion each year, all of which ought to instead be spent on vital infrastructure and frontline services.

There are, however, reasons for optimism. Through a combination of coordinated cross-government engagement, prioritised CMA enforcement and strategic private litigation, we can level the playing field in the war on bid rigging, promoting fairer competition and making collusion harder, riskier and more expensive for those who attempt it.

Footnotes

[1] https://commonslibrary.parliament.uk/research-briefings/cbp-9317/

[2] Financial Times: “UK competition watchdog seeks to work with MoD to curb bid-rigging”, 8 September 2026.