Three more MPs have succumbed to intense pressure over their expenses by saying they will not seek re-election.

Tory backbencher Julie Kirkbride said the situation had become “unbearable” as she followed husband Andrew MacKay in announcing her departure from Parliament at the next General Election.

Almost simultaneously the Labour MP for Luton South Margaret Moran said she would be stepping down, complaining that the furore over her £22,500 dry rot claim had damaged her health.

And last night Conservative Christopher Fraser — who claimed more than £1,800 to buy 215 trees and fencing — said he was standing aside in South West Norfolk. He stressed the move had “nothing to do” with the expenses issue.

The pain for all three will be eased by substantial Commons “redundancy” pay-offs — more than £54,000 for Ms Moran, and some £32,000 for Ms Kirkbride and Mr Fraser. The first £30,000 will be tax-free.

Despite vowing to fight on on Wednesday night Bromsgrove MP Ms Kirkbride telephoned David Cameron yesterday morning to tell him she was going in the face of “distorted” media coverage that was damaging her family.

“I understand people’s anger about MPs’ expenses, but I have been subject to a barrage of distorted Press stories which I have sought to rebut,” she wrote in a resignation letter to Mr Cameron.

“As you said yesterday, I gave a good account of myself. But the fact that I am still defending myself and my family two weeks after Andrew stepped down as your adviser has now become an unbearable pressure.”

She added: “This pressure on my loyal party workers and me has to end.”

Mr Cameron responded that Ms Kirkbride, who denied any wrongdoing, had “given full answers to the questions that have been put to you, and you have given a good account of yourself”.

He wrote that the public were “rightly angry” about expenses revelations, and urgent reform was “essential”.

“But it is also extremely important that part of that reform includes better ways of enabling women to combine the roles of politician and mother,” he added.

The MP couple had used £170,000 in Commons allowances to fund both homes where they lived over four years.

Former shadow Northern Ireland Secretary Mr MacKay’s arrangements were considered more serious because he was receiving allowances to fund their London home despite not having a property in his constituency.

But his sacrifice last week failed to quell public anger and Ms Kirkbride came under fire for employing her sister as a part-time secretary — even though she lived in Dorset, 100 miles from either Westminster or Bromsgrove.

The final blow appeared to have been struck yesterday when she was attacked for using taxpayers’ money to part-fund a £50,000 extension at her constituency flat so her brother could stay and help with childcare.

Meanwhile, Ms Moran released a statement saying: “The understandable public anger over the issue of MP’s expenses has caused me great stress and has seriously worsened my health problem.

“It is with great sadness that I have today informed the general secretary of the Labour Party following discussion with my family that I intend to stand down as a MP for Luton South at the next general election.”

The MP had become notorious for designating a property in Southampton as her second home, nearly 100 miles from her constituency, before days later claiming £22,500 to treat dry rot.

Who’s really to blame for expenses furore? See Page 31