The government is going to be under pressure to replace two senior members of its IT team, as it emerged that David Pitchford, who heads up the Major Projects Authority (MPA), and Paul Marriner, executive director of Next Generation Shared Services (NGSS), will both step down.

Pitchford established the MPA in 2011, where the Cabinet Office said he has been responsible for driving up by a third the performance of the £414 billion major projects portfolio from 2010 to 2013.

Under Pitchford's leadership, this government has also been the first to make transparent all major projects data, which helped both scrutiny and the general efficiency drive and delivred £1.2 billion savings last year.

The MPA chief also did a stint at the Department for Work and Pensions recently, where he headed up the troubled Universal Credit project for three months after a number of changes in leadership left questions surrounding the success of the roll-out.

Francis Maude, Minister for the Cabinet Office, said: "David has led the Major Projects Authority brilliantly and has been a major player in the Efficiency and Reform Group's top team, which is working to transform Whitehall and save the taxpayer billions.

"The authority's first annual report was a watershed moment. For the first time ever, we disclosed an honest appraisal rating for each of the Government's major projects."

He added: "This transparency will help further drive up standards, ensuring the billions of pounds that we spend on projects are properly focused. And besides all of this, I will much miss David's sharp wit and impressive leadership. I wish him all the best for the future."

Separately, the executive director of Next Generation Shared Services, Paul Marriner, said he will also leave the Cabinet Office. A spokesperson for said that the NGSS programme, which is critical to the Civil Service Reform Plan and aims to use industry best practice to delivery back-office functions more efficiently, will be delivered on time with the expected benefits.

Marriner's departure comes as the programme moves from development to implementation, according to the Cabinet Office, and it is estimated that it will delivery up to £600 million of saving per annum.

"The NGSS programme has achieved a phenomenal amount over the last year and Paul leaves the programme in a fantastic position to deliver on all its targets," said Government Chief Operating Officer Stephen Kelly.

"I wish him all the best in his next endeavour. With implementation of the NGSS strategic plan fully under way, a clear path for delivery established, and support to ensure the programme fulfils its potential, he leaves the initiative in a strong position as it enters the next phase of delivery."