The government needs to bring in "thousands" of digital tech folk to lower the high number of failing IT transformation projects, the chief executive of the civil service has said.

Addressing the Public Accounts Committee about findings that one-third of big government projects will fail in this Parliament, John Mazoni said transformation projects need far more digital and commercial bodies on the ground.

"We are taking steps to significantly ramp up the pace at which we are bringing these in," he said. "It’s hundreds in the commercial area; it’s probably thousands in the digital area. We have to bring those [roles] in."

Tony Meggs, chief executive of the newly named Infrastructure and Projects Authority, was also grilled by MPs about the body's portfolio of 149 high risk projects with a combined lifetime value of £511bn.

When asked by the committee which three projects in the portfolio kept him awake at night, Meggs named the Cabinet Office's shared IT services programme "because it is not going very well at all." He said: "The project has suffered from not having been set up well and some of [its] complexities were misunderstood."

The Register has documented the problems around the privately run shared services centres, with at least two departments having dropped out the scheme.

Meggs also mentioned the high speed rail HS2 project and transformation projects such as the plans to reform courts with technology.

Discussing a number of "digital transformation" projects to have come under scrutiny by the PAC, Mazoni highlighted Universal Credit, the Common Agricultural Policy IT system and e-borders as sharing a common issues.

"They happened right at the moment that we were learning about how the new technologies can be applied and how digital technology can be applied to business processes," he said. "We were over ambitious about what those new technology could bring," he said.

He said government has now learned that big projects are neither "waterfall" - a phrase used in software development to describe a sequential design process – or "agile", a term used for iterative development. "They are a mixture of both." ®