Ernst & Young is expected to be appointed today as administrator to Metronet, the Tube contractor.

The firm will be called in after two days of intense meetings between the company and its five shareholders, WS Atkins, Balfour Beatty, Thames Water, France's EDF Energy and the Canadian train maker Bombardier, according to reports.

It is understood the companies have concluded they have no prospect of making a return from Metronet without up to £2bn of extra funding. They have refused to put up any more of their own cash beyond the £70m each invested at the start of the public-private partnership to upgrade the London Underground that was championed by Prime Minister Gordon Brown while Chancellor of the Exchequer.

The administrator’s job will be to ensure that work continues while attempting to find a new operator to take on the work and the debt. If one is not found the contract, and debt, will revert to Transport for London.