He will take on some of the roles of his previous Pensions Minister position until a new Prime Minister is selected following the resignation of Boris Johnson.

He said the role is a temporary one for the next few weeks while the Conservative Party choses a new leader.

When the new leader of the party takes over as Prime Minister, they will appoint a Pensions Minister to replace him although it is also possible he may return as Pensions Minister.

Mr Opperman said he has agreed to help the DWP navigate the next few weeks including current discussions and legislation around the cost of living support, the expansion of pension credit, Pensions Dashboards, superfunds, defined benefit issues, an outstanding ESG consultation, ongoing correction exercises, and several pending Private Members Bills.

He said on his social media that he was asked to step in to the caretaker role by the Chief Whip.

Mr Opperman resigned from his role as Pensions Minister on Thursday, as one of many senior Government ministers to resign to put pressure on Prime Minister Boris Johnson to step down. 

Mr Opperman served as Pensions Minister since June 2017 and his five-year tenure made him one of the longest serving Pensions Ministers.

Mr Johnson announced he would step down as Conservative Party leader on Thursday lunchtime, but will continue as Prime Minister until a new leader is chosen.

In his resignation letter to Prime Minister Boris Johnson, Mr Opperman wrote: “I am proud of what we have achieved at the DWP. I want to put on record my thanks to the DWP civil servants and ministerial teams I have worked with to produce and pass five Acts of Parliament, grow workplace and state pensions to record levels, and passing the ground-breaking Pension Schemes Act that dramatically reforms pensions in the UK.

“I could go on, and there is much more reform I would have liked to have done, but I have to ask you to step aside.”

In the letter he wrote that he had been, “particularly upset at the behaviour of the Number 10 team during the Covid restrictions” and “recent events have shown clearly that Government simply cannot function with you in charge.”