North West Conservative MEP Den Dover faces a criminal investigation, has been expelled from his own party and ordered to repay more than £500,000 after an inquiry found him guilty of expense abuses.

Dover, who represented the Chorley constituency in Parliament from 1979 to 1997 and is currently a MEP for North West England, paid £758,146 over seven years to a company run by his wife and daughter.

The company also made a donation to the Conservative Party last year of £1,200.

Mr Dover had the Conservative whip withdrawn yesterday after Tory leader David Cameron intervened after hearing the results of the inquiry conducted by the European Parliament.

The inquiry found that Mr Dover had a conflict of interest in using the firm M P Holdings for secretarial and parliamentary assistant work.

He had earlier declared he had no financial interest in the family-owned company that employed his wife, Kathleen, as secretary and daughter, Amanda, as part-time assistant.

Both his wife and daughter are directors of the company.

Mr Dover was informed by Harald Romer, the European Parliament's secretary-general, that the expenses probe had found there was ‘unaccountable expenditure’ of more than £500,000 during the period.

Mr Dover was unavailable for comment this morning.