OUTSPOKEN Essex MP Andrew Mackinlay has come out fighting amid the "cash for families" controversy at Westminster.

Revelations Derek Conway, the Tory MP for Bexley and Sidcup, has been cashing in by giving his sons and wife lucrative jobs at the public's expense have brought the spotlight on other Commons members who employ their families.

Mr Mackinlay, Labour MP for Thurrock, employs his wife Ruth as his assistant.

But he said he was confident he had done nothing wrong, claiming his wife of 36 years gave taxpayers value for money.

Mr Mackinlay accepted the public had cause for concern after the excesses of Mr Conway were brought to light, but said he had nothing to hide.

He said: "Unfortunately, the actions of a small and selfish minority cause the vast majority of MPs considerable and unfair embarrassment.

"What I can say is my wife, Ruth, who gave up a much more highly paid senior teaching position to work with me, has worked for me and with me each day at Westminster for many years.

"I know many thousands of people, particularly those from Thurrock, who come in to contact with her, and know of her extremely hard work and diligence and, above all, sensitivity.

"Ruth works for me because she believes in what we do together as a team and because we share a common belief."

Former nurse Marian Wright, 61, of Botany Terrace, Purfleet, who recently retired from a post at the House of Commons, said she had first-hand experience of how hard the couple worked.

She said: "I worked at the Commons for seven years and I can honestly say people don't realise how hard they work and what Ruth Mackinlay contributes.

"If he employed anyone else, he wouldn't get anywhere near the value for money that he does now. She's one of the best."

Meanwhile, Tory MP Derek Conway has announced he will step down at the next election, after embroiling the Conservatives in "sleaze" allegations over payments to his family.

The Old Bexley and Sidcup MP decided to quit the Commons after further talks with Chief Whip Patrick McCloughlin, as Scotland Yard confirmed they had received a letter of complaint over the affair.

A senior Tory source said simply: "Derek has done the right thing. We can now move on."

Mr Conway said in a statement released by the party: "I have had tremendous support from my local party, my family and friends but have concluded that it is time to step down.

"Since joining the Conservative Party nearly 40 years ago I have had the privilege of serving in public office since 1974 and have done so to the best of my ability. I have advised the Chief Whip and the chairman of my local Conservative Association that I shall not seek to continue as the Conservative Party candidate for Old Bexley and Sidcup at the next election.

"Though not an original supporter of David Cameron for the leadership of my party, I believe that he has shown he has both the ability and the character to be Prime Minister of our country and I do not wish my personal circumstances to be a distraction in any way from the real issues that have to be addressed."

Mr Conway, who was earlier stripped of the Tory whip, was found to have "misused" parliamentary funds by paying an annual £11,773 salary, plus bonuses totalling more than £10,000, to his younger son Freddie while he was a full-time student in Newcastle.

The Commons Standards and Privileges Committee found the arrangement was "at the least, an improper use of Parliamentary allowances: at worst, it was a serious diversion of public funds".

MPs will vote on its recommendation that Mr Conway should be suspended from the Commons for 10 days and required to repay up to £13,161 of the cash.

He also now faces a possible police inquiry and fresh sleaze investigations into complaints about payments made to his other son, Henry. Scotland Yard confirmed that it had received a letter from Duncan Borrowman, the Liberal Democrat challenger for the MP's parliamentary seat, asking officers to examine whether a fraud had been committed.