Linklaters and KPMG are to split a pot of £5m for a two month investigation into the accounts of building company Interserve.

In August. Interserve launched an investigation and suspended six senior managers from its industrial services division, which has clients including Heathrow Airport and BP, after finding a £25.9m hole in the accounts.

Linklaters expects the full report to be finished by mid October.

The company appointed London corporate partner Mark Stamp and London litigation partner Alan Walls to lead the legal investigation, with a large KPMG team brought in to carry out a forensic accounting investigation.

A spokesperson from Interserve said: “The bulk of [the £5m bill] is going to KPMG. The figure is just an estimate at this stage. The investigation is still going on and there are still issues over who did what when.”

The deal has a high value for Linklaters corporate team, with the firm likely to pick up between £1m and £2m for two months work.

“We have not yet done the breakdown between the two,” said Interserve.

The details of the cost investigation fees emerged when Interserve released its interim figures last week. Interserve’s revenue is £1.4bn worldwide.