Conservative MP says he will co-operate with any probe into work for security firm

Mr Mercer has been MP for Newark since 2001

Tory MP Patrick Mercer has said he will co-operate fully with any investigation by a Commons watchdog into his relationship with a security firm.

Labour's Thomas Docherty has written to the Parliamentary Commissioner for Standards asking him to look at whether his Tory counterpart broke any rules.

Mr Mercer sponsored a Commons pass for the head of Clearwater Security while being paid by it for consultancy work.

The MP said none of his work for the firm had taken place within Parliament.

The BBC's Political Correspondent Gary O'Donoghue said the payments from Clearwater, amounting to more than £9,000 over a year, were declared in the register of members' interests.

Mr Mercer, who is travelling abroad at the moment, told the BBC that none of his consultancy work for Clearwater had been conducted on the Parliamentary estate, which would be a breach of the rules.