Tony Blair has defended the government's record on pensions despite claims that the country is sitting on a pensions timebomb.

The prime minister came under fire from Iain Duncan Smith, who blamed pension fund taxation and a £350 billion fall in the value of stock market for a "crisis" in the industry.

Telling Blair not to listen to his Gordon Brown, his neighbour both on the government frontbench and in Downing Street, the Conservative leader asked "how much longer a man of his age is going to have to work now to receive a decent pension"?

"Four years longer," claimed Duncan Smith.

"Does he now accept that because of his imposed pensions tax millions of people's retirement plans are now in ruins?"

Blair came back fighting, telling the Tory leader his figures were wrong and that he could expect a 40-year wait, or more, before entering government.

"It really is absurd to say the chancellor is responsible for the fall in the stock market, yes the stock market has fallen, but it is still massively up on where it was five years ago," Blair told MPs during question time exchanges.

Citing stakeholder pensions and new credits, the prime minister said the government had put "£6 billion more into pensions every year"."What pensioners remember is the last Conservative government and the mis-selling of pensions scandal, and them doing absolutely nothing about it.

"So Mr Speaker whether my longevity or his is the issue I don't think a Conservative government is the answer."