The private investigators hired to find Madeleine McCann were embroiled in fresh controversy last night as it was revealed they claimed nearly £50,000 in expenses for one month's work.

US-based firm Oakley International was taken on by the Find Madeleine Fund earlier this year on a ?500,000 six-month contract to monitor a telephone hotline, carry out detective work and review CCTV footage from around the world of possible sightings of the missing girl.

The company was selected by double-glazing tycoon Brian Kennedy, who has pledged to support the McCann's financially until the mystery of the disappearance of their daughter is solved.

Madeleine has not been seen since May last year, when she disappeared from the family's apartment in the Portuguese holiday resort of Praia da Luz shortly before her fourth birthday.

However, Mr Kennedy became concerned by Oakley's $74,155 expenses claim in the first month of the contract, and the lack of receipts.

This newspaper revealed last month that the company's contract was terminated at the end of August after Mr Kennedy had become concerned at its lack of results.

Clarence Mitchell, spokesman for the Find Madeleine Fund, confirmed that Oakley International was not now working on the case.

He said: ?The contract with Oakley was just one among many that have been entered into during the search for Madeleine. While Oakley did some valuable work, particularly in the early stages, its contract, like many others, has now come to a close.

?The search for Madeleine is continuing, however, using other resources and the performance of other contractors is constantly reviewed and monitored. Kate and Gerry and the backers will leave no stone unturned in the search for Madeleine.?

Former police officers are now being interviewed by Mr Kennedy to take over responsibility for the investigation into Madeleine's disappearance.

Mr Kennedy, 47, estimated to be worth about ?250million, made his money in double-glazing and home-improvement ventures with companies including Everest windows.

He became involved with the McCanns after being moved by their plight during the period they were made formal suspects ? arguidos ? in Madeleine's disappearance.

Portuguese prosecutors dropped the couple's arguido status in July.

Oakley International said: ?We carried out our instructions from the Fund professionally and responsibly in accordance with our agreement