The Work and Pensions Committee backed the government’s move to a single-tier flat-rate state pension of about £144 a week, however, it warned the policy’s success hinges on how the government communicates.

It also criticsed the government for its ‘cavalier’ move to bring forward the changes by 12 months.

Dame Anne Begg, committee chairman, said: “This is a major reform which will affect all 40 million people of working age. Although the end result will be simplification, the transition period will be long and complex.”

She said people needed information on how they would be affected.

“There are already misconceptions about who stands to gain and who might lose. People closest to retirement understandably have the most immediate concerns. So it is vital that the government decides on its high-level strategy for communicating the changes to the public by the time the finalised Bill comes before Parliament in the summer.

The government had originally planned to make the changes in April 2017, however, it was brought forward by 12 months to April 2016.

The Work and Pensions Committee criticised the government for the ‘cavalier’ decision, saying ministers had given it a tight timetable to assess the bill.

Begg said: “We agreed to the government’s request that we carry out pre-legislative scrutiny of the proposals. This process is a vital mechanism in ensuring that significant reforms receive rigorous and effective scrutiny.

“I am disappointed that the government has hampered us in carrying out this task, by giving us very little time to do it, due to the delays in its own timetable for publishing the proposals, and then making a major change to the policy at a very late stage.

“Such a cavalier attitude to the scrutiny role of select committees is unacceptable. Nevertheless, we believe our recommendations are valid and that our findings will assist Parliament when it considers the finalised Bill in the summer.”