Keith Vaz should stand down as Leicester East's MP – So says a constituent who has left the Labour Party over Mr Vaz's response to the expenses row. Lee Marlow reports.

For more than 30 years, Liz Warren has been a paid-up member of Leicester East Labour Party. That association has come to an abrupt and very public end. The former head teacher, of Evington, is quitting the party she once loved – and calling on her MP, Keith Vaz, to stand down.

Her letter to Mr Vaz is printed below.

It follows a story in the Mercury about former independent MP Martin Bell saying the search for an independent candidate to challenge Mr Vaz was under way.

Miss Warren, former head of Mundella Community College, says in her letter to Mr Vaz that she feels "ashamed even to admit that I live in Leicester East, let alone that I was once so supportive of you".

She met Mr Bell in London during the summer.

"It was a good meeting and I was interested to hear what he had to tell me," she says.

"I agree with him that an independent challenge to Mr Vaz in Leicester East is desperately needed."

She tried to persuade the former BBC Foreign Affairs reporter to stand in Leicester East. He politely declined.

But Mr Bell did tell the Mercury this was not the first time he had been asked to stand against Mr Vaz.

"I was approached in 2001 to stand as an independent candidate against Keith Vaz in Leicester East," he said.

He met a small but influential group of "very decent" businessmen and listened to their concerns.

"I sympathised with them, too," he said. "But I couldn't do what they wanted me to do. By then, I had more or less committed myself to standing in Brentwood."

Ms Warren says she has been a member of the Labour Party since she moved to Leicester in 1977. Quitting the party, she says, is a decision she hasn't taken lightly.

"I feel, however, that the Labour Party has left me, rather than me leaving the party. The expenses issue was the last straw, particularly here and the items claimed by Mr Vaz.

"I felt very strongly that he let us down – the party members who have worked hard and canvassed for him but also the constituency of Leicester East.

"I feel a sense of personal responsibility, too, for my part in this, in supporting him and helping him to be elected."

The letter was delivered last week. In response, Mr Vaz released a statement

It said: "Liz Warren has been disenchanted with the Labour Party for some time.

"We have had discussions about this.

"In particular, several years ago, the school where she was head teacher closed due to education reasons by the city council.

"Unfortunately, MPs cannot satisfy each and every one of their constituents, although I have tried to deal with all the concerns which Liz has raised with me.

"We live in a parliamentary democracy and people are perfectly able to stand for Parliament as independent candidates if they chose to do so. Leicester has a long tradition of independent candidates.

"I was particularly pleased to hear the kind comments Martin Bell made about me on Radio 5 Live. I look forward to meeting Liz again in the future."

Read Mrs Warren's letter to Keith Vaz