Transport for London will lodge a formal bid next month with Ernst & Young LLC, Metronet's court-appointed administrator, the agency's spokesman, Dan Hodges, said in a phone interview today.

Metronet maintains two-thirds of the railway and has 5,000 employees. The company's collapse may undermine the U.K. capital's largest investment since World War II in the 144-year- old London Underground. City officials said taking over Metronet will be the quickest way to remove it from administration.

The insolvency process is ``very complex and very expensive,'' said Hodges. ``We want to bring Metronet out of administration, and this is the fastest and most efficient way.''

The city set aside 900 million pounds ($1.8 billion) to fund Metronet's administration through the end of the year. The financial details of the bid weren't given.

Transport for London has expressed its interest to the administrator, said Vicky Conybeer, an Ernst & Young spokeswoman, in a telephone interview. There have been no other bids so far for Metronet, she said.

London Underground performed its own maintenance until 2003, when Metronet won a 30-year contract for work on nine of the railway's 12 lines. Tube Lines Ltd., a separate private company, does the work on the other three lines.

Three rail unions have called for the city to take over Metronet. The unions yesterday said they're planning two 72-hour strikes against the company, starting Sept. 3 and Sept. 10, to protest possible job cuts. The walkouts may disrupt service.

Metronet collapsed after saying it ran up about 2 billion pounds in extra costs. The company was a joint venture owned by WS Atkins Plc, Balfour Beatty Plc, Bombardier Inc., Thames Water and Electricite de France SA.