Alan Johnson described the government’s cuts as “ideological” and dismissed an attempt by the coalition to suggest its measures were less severe than Labour’s might have been.

Two weeks into his new role, the shadow chancellor put in a performance that went some way towards reassuring Labour backbenchers that he will be an effective opponent to George Osborne.

While accepting that the deficit “has to be paid down”, he described the coalition’s four-year spending plan as a “reckless gamble with people’s lives”.

Johnson said that, in the fullness of time and despite tables in the comprehensive spending review documents which the government said showed the richest taking the greatest burden, the poorest would bear the brunt.

He also said – repeating an Ed Miliband argument – that “the middle” would be squeezed further and that women would shoulder the burden of three-quarters of the cuts.

Quoted in the Guardian, Mr Johnson continued “Today is the day that abstract figures and spreadsheets turn into people’s futures, people’s jobs, people’s pensions, people’s services,”.

In cutting welfare, Osborne told Johnson his cuts to departmental budgets had actually come in at lower than Labour had planned: an average of 19% – just under the 20% that would have been the case under Labour.

Johnson said the comparison was inaccurate. He said Labour would support two of the Tory benefit changes, so bringing down their spend.

Labour had also made changes to its tax and spend policies since going into opposition, he added, introducing revenue-raising policies including a rise in capital gains tax and a freezing of the tax threshold as well as an increase in the proposed bank levy.

The party said its acceptance of the recent coalition reforms to welfare meant spending cuts would be £20bn lower under Labour and it would cut departmental spending by half the level that the government has.

Johnson said Osborne was simultaneously trying to claim his cuts as equivalent to Labour’s and accuse the opposition of not having a credible deficit reduction plan.

Johnson was theatrical in is response to numerous Tory MPs waving their order papers – apparently with excitement – during Osborne’s announcement: “Members opposite are cheering the deepest cuts in public expenditure that have taken place in living memory. For many of them, this is what they came into politics for.”

Johnson made light of the fact that, during the last comprehensive spending review in 2007, Osborne had supported Labour’s spending plans until after the scale of the credit crunch became apparent “well after the collapse of Lehman Brothers in America set off a disastrous chain reaction around the world”.

The Liberal Democrats, he said, had changed position on whether cuts would be justified this year between the ballot box closing and the door of the ministerial car opening.

Osborne mocked the shadow cabinet for saying they would not put forward their own spending plans. Johnson, he suggested, “doesn’t even have a plan B, and there is complete denial about the fact that the country has the largest budget deficit in the G20.