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Questions over size of government’s legacy IT estate pose AI adoption issues

Two House of Commons committees have turned their attention this week to the lack of transparency concerning the size of the government’s legacy IT estate, and what this means for its ability to adopt artificial intelligence technologies

Caroline Donnelly
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Published: 16 Oct 2025 14:22

Whitehall’s ability to adopt artificial intelligence (AI) technology risks being hamstrung by the government’s reliance on an unknown amount of legacy IT, according to the output of two separate House of Commons committees this week.

The Science, Innovation and Technology Committee, which exists to examine the output and policies of the Department for Science, Innovation and Technology (DSIT), touched on the topic of legacy IT during an oral evidence session held on 14 October 2025.

The session, which was part of an ongoing inquiry by the committee into the work DSIT is doing to establish itself as the new “digital centre for government”, featured submissions from the Institute for Government and Crown Hosting Data Centres.

Nick Davies, programme director at the Institute for Government, outlined the difficulties in trying to get an accurate picture of how much money the government spends on digital transformation in general.

“Data on spending is mixed at best [including] the quality of it … but, historically, it has been quite difficult to connect the contract data with the spending data,” he said. 

“Market intelligence firms will be able to give you a better guess at it, but it is not as precise as it could be,” he added.

The roll-out of The Procurement Act in February 2025 was intended to increase the visibility of government spending by introducing requirements that full contract details for tech deals in excess of £5m should be published within 90 days, for example.

The idea being that this would make it easier for spending watchdogs, competing tech firms and the general public to get unprecedented visibility into how and what the government is spending its money on.

However, progress on achieving that has been “a little bit mixed”, according to Davies.

“Use of all of the different types of [contract] notices [required under the terms of the Procurement Act] is growing month on month. However, some parts of government are still publishing fewer notices than they were before the act came into force,” he said.

“That could be a sign of non-compliance, or it could be, for example, that procurement authorities are choosing not to voluntarily publish notices. But, in theory, the act should improve [transparency].”

How much legacy IT does the government have?

And while question marks remain over how much money the government is spending on new technology, there are also difficulties in working out how big the government’s legacy IT estate actually is, the committee also heard.

This topic was touched on during the committee hearing by Jason Liggins, CEO of Crown Hosting Data Centres, which is a joint venture operated by the Cabinet Office and colocation firm Ark Data Centres.

The organisation is, according to Liggins, the largest datacentre supplier in the UK. It was set up in 2015 to help public sector operators consolidate their legacy datacentres and server rooms by providing access to more efficient facilities where they could host their workloads.   

“Our job in Crown Hosting is to save the public sector money, cut energy use, reduce carbon and accelerate digital transformation,” said Liggins. “And we already help [the] public sector save £1.5bn per year … by moving legacy IT from the server rooms and cupboards across the public sector to very large, highly efficient facilities.”

As an example of this work, Liggins cited the Department for Work and Pensions (DWP) as a key customer of Crown Hosting, which it worked with to relocate data and applications to a private cloud setup within its facilities over the course of nine months.

The project was part of a broader, wholesale move to the public cloud by DWP, which has, to date, taken seven years, with 70% of the department’s services now hosted in the public cloud.

According to Liggins, the move into Crown Hosting by DWP enabled the department to save £150m a year on its legacy IT costs and achieve its desired return on investment in nine months.

In response to these figures being shared, committee member and Labour MP Chi Onwurah asked how much legacy IT exists across government, and how it is measured, given that the State of digital government review “effectively” found that departments do not have a record of the “legacy assets” they hold.

In response, Liggins said there are mechanisms in place that provide a partial steer on how much legacy IT is in use across government, including one operated by HM Treasury whereby departments must document how much electricity is used by their IT systems each year, for the purpose of carbon impact reporting.

“Defra [the Department for Environment, Food and Rural Affairs] analyses those figures on behalf of all departments to work out carbon savings,” said Liggins. “All of the carbon impact [documented in those figures is considered] legacy IT, and that’s because the cloud providers don’t return their [carbon] figures.”

On this point, Onwurah asked for clarification if, by that definition, it means the government considers all non-public cloud IT assets to be legacy, to which Liggins confirmed it does.

“I have a particular opinion on the terminology government uses, in that [in their view] all non-public cloud IT assets are legacy, no matter whether they’re old, new, or contemporary,” he said.

In response, Onwurah said: “We can agree that’s an interesting definition … so [are you saying] to the committee that the government does know what and where its legacy is by its own definition, by looking at power consumption?” To which Liggins confirmed that take was correct.

The Public Accounts Committee (PAC) also touched on the topic of legacy IT in its annual report, published on 15 October 2025, which is the first published by the organisation’s latest chair, Geoffrey Clifton-Brown.

The PAC report flagged the persistence of “out-of-date legacy IT infrastructure” as a “major challenge” to the implementation of artificial intelligence (AI) technologies across government, while increasing departments’ exposure to cyber attacks.

The report cites DSIT’s definition of legacy IT systems, which describes them as “end-of-life products, out of support from the supplier, impossible to update, no longer cost-effective, or considered to be otherwise above the acceptable risk threshold”.

By this definition, it states that an estimated 28% of central government systems met this definition in 2024, which the report described as “extremely problematic” for the government’s AI adoption plans.

“However, DSIT does not know how many legacy assets there are in total across government. This is wholly unacceptable in the context of an increasingly hostile digital world,” said the report.

“While government has unveiled its plans to address this problem in [DSIT’s January 2025] A blueprint for a modern digital government [policy document], we remain extremely concerned by the scale of the challenge [so] funding for the remediation of the highest-risk legacy technology must be urgently prioritised.”

The report added: “Our committee recommended that the government should establish an approach for measuring the costs associated with addressing legacy technology, as well as the costs of failing to act, to increase transparency and improve decision-making.”

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