A former West Midlands MP has made a grovelling apology to the House of Commons after he paid his son more than £40,000 to be a researcher - while he was also a full time student.

Derek Conway apologised for "the misjudgments I made" after he was found to have misused his staffing allowance, which is provided by the taxpayer.

The MP, a former Conservative whip, represented Shrewsbury in Shropshire from 1983 to 1997. In 2001 he became MP for Old Bexley and Sidcup.

Yesterday he said he fully accepted criticisms by the Commons Standards and Privileges Committee, the official watchdog for MPs.

Mr Conway told MPs: "No judgment from any quarter could be more harsh than that which I apply to myself." He faces a 10-day suspension from the Commons after the committee found he "misused" his MP's staffing allowance to pay his son an "excessive" salary.

The committee found Mr Conway had employed his son Frederick as a part time research assistant from September 2004 to August 2007, on a salary of £11,773 per year.

On top of this, his son received four bonus payments which came to a total of £10,065.94.

Frederick was 19 when the arrangement began, and about to begin a full-time under-graduate course at Newcastle University.

The committee concluded there was little evidence he had actually carried out any work to justify the payments.

In a damning report, it said: "We note that Frederick Conway seems to have been all but invisible during the period of his employment.

"For the majority of that time he was based at Newcastle where he was engaged in a full time degree course at the university."

It added: "This arrangement was, at the least, an improper use of parliamentary allowances: at worst it was a serious diversion of public funds. Our view is that the reality may well be somewhere between the two."

The committee recommended Mr Conway be suspended from the Commons for 10 days, and should repay up to £13,000.

The whole House must now decide whether to accept the recommendation.

Yesterday, Mr Conway apologised to his fellow MPs. He said: "The committee was entitled to reach the conclusions it did and I have accepted their criticisms in full."

He added: "In apologising to the House, I would also like to apologise to my constituents and to the Old Bexley and Sidcup Conservative Association, which has been so very supportive to me and my family throughout a very difficult period. The House will comprehend the impact this matter has on me personally, but also on my family, I have let them down very badly indeed and no judgment from any quarter could be more harsh than that which I apply to myself."

The MP lost his Shropshire seat in the Labour landslide of 1997, when Tony Blair led his party to General Election victory. Rather than fight to regain the seat, he became candidate for the safe Tory seat of Old Bexley and Sidcup, in London.

The committee's findings were based on an investigation by former Parliamentary Commissioner for Standards, Sir Philip Mawer.

It was triggered by a complaint from Michael Barnbrook, a retired policeman who stood against him as a candidate for the UK Independence Party, and is now a member of the British National Party.