Pensions Minister Steve Webb has denied "hoodwinking" voters over the government's plans to change pension rules.
At work and pensions questions on 23 April 2012, Labour's Liam Byrne claimed that pensioners would be "£315 a year worse off, thanks to the granny tax".
The figures had been provided by the Institute for Fiscal Studies, a think-tank, the shadow work and pensions secretary said.
Mr Byrne ridiculed the government's decision to bill the pension changes as a "simplification".
Did Work and Pensions Secretary Iain Duncan Smith go to the barbers and "ask for his hair to be simplified?" Mr Byrne demanded.
"No, because a cut is a cut."
He concluded: "This is why pensioners on the doorstep are so cross, because they know they've been hoodwinked by this government."
Mr Webb dismissed Labour's claims, arguing that the government had "good news for today's pensioners - both the highest ever cash increase but more than that year-on-year, above inflation increases whenever earnings grow more rapidly".
Although the age-related personal allowance for pensioners would be frozen from next year, Mr Webb added, it would be increased by £500 this April.
He received support from Liberal Democrat deputy leader Simon Hughes: "The Budget and the decisions of the government have been the best news ever for pensioners now, as well as being the best news ever in the future.
"The press and the opposition appear to have missed the point," Mr Hughes lamented.
Other questioners focused the attention of the House on support for Remploy workers, the universal credit and childcare, and health and safety regulation.