Advisers are facing further scrutiny of the value of their public sector work, after MPs called for the National Audit Office to re-examine the collapse of tube upgrade company Metronet.

Research by Accountancy Age shows Ernst & Young, PricewaterhouseCoopers and KPMG have earned almost £25m from advising on Metronet, which may be further scrutinised in a possible NAO probe.

The National Audit Office is considering requests from MPs to investigate the consortium’s collapse. The NAO has received a written request from shadow transport secretary Theresa Villiers to investigate Metronet, including the fees paid to advisers, and is currently considering whether it should proceed with an enquiry.

Twickenham MP and Lib Dem Treasury spokesman Vince Cable said: ‘The government paid more than £500m to accountants and other consultants over the PPP agreement. Now that this agreement has collapsed we must ask where all that money has gone.’

A probe would not be the first time the government has looked into the issue, but it could raise damaging questions about consultants’ work for the public sector. There is no suggestion that any of the three firms have done anything wrong.

According to figures submitted to the Public Accounts Committee in June 2004, PwC, as the lead financial adviser to the London Underground ahead of the Public Private Partnership (PPP), earned £21.4m.

KPMG earned £2.4m for auditing public sector methods for assessing the value of the bids for the tube contract for London Underground.

Ernst & Young earned approximately £1m for advice to both London Underground and the Department for Transport, separate parliamentary records reveal.

Both KPMG and E&Y are set to earn further fees from the issue too. E &Y’s Alan Bloom appointed as administrators last week and KPMG are advisers to the PPP arbiter.

Metronet was plunged into administration last week when the PPP arbiter refused to grant the consortium’s request for £551m in emergency funding.

None of the firms would comment on a possible probe.