The Conservatives have called for an investigation into claims that former MP Peter Law was offered a peerage not to stand against an official Labour election candidate.

Shadow Wales secretary Cheryl Gillan asked Tony Blair to conduct an investigation after the allegations were made by Law’s widow.

In a letter delivered to the prime minister, Gillan demanded to know what Blair’s response is to the allegations made by Trish Law on BBC Wales.

"Given the limited time scale between the interview and the denial, which 'senior Labour politicians' were contacted last night about the allegation, which government minister authorised the denial, and what inquiries did he or she make before issuing the rebuttal?" asked Gillan.

Prior to the last general election, Law, who died this week, had left the Labour Party following a row over the use of an all-women shortlist.

In a shock result, Law defeated official Labour candidate Maggie Jones in the Blaenau Gwent constituency. Jones has since been put forward for a peerage herself.

But Labour in Wales was keen to avoid a damaging split in its vote, his wife, Trish, told BBC Wales.

"There was pressure put on him. He had quite a number of phone calls from high-ranking politicians not to do it, [they said] he would be silly to do it, there was no way that he would win," she said.

She said she believed a peerage was a serious proposition, otherwise "Peter would not have said it to me".

"That's quite a lot of pressure and it was pressure at the time when he was, when he was quite ill as well you know, but Peter couldn't be bought."

Asked who had offered the peerage, Mrs Law said: "I would prefer not to but there were quite a few, there were quite a few politicians who were ringing him on a regular basis, telling him as well that he'd be a fool to stand against the Labour Party."

But a Labour Party spokesman insisted: "Friends of Peter from within the party did plead with him not to stand and that's well known, but there was no offer of a peerage."