Nineteen thousand staff reorganised, launched on the published date.

The Ministry of Justice was reorganising 19,000 staff and opening the management of low and medium risk offenders to new providers. The change was designed at headquarters. The risk sat in the operational business, which had to keep supervising offenders every day while it went through.

There was no tolerance for a dip in performance, because a dip in performance meant a risk to the public.

We set up a programme assurance function that sat outside the programme and reported straight to the senior responsible owner. It was the first of its kind in central government.

Before every decision gate it asked one question: is the operation ready, on evidence rather than on assurance from the people who wanted to proceed? Every function, supplier and adviser was tested against the same criteria and the operational KPIs, and each gap came with a risk rating and the action that would close it.

The point was not to mark the programme’s homework. It was to find the problems while there was still time to put them right.

The programme launched on its published date. Probation became one National Probation Service and 21 Community Rehabilitation Companies, run by eight major providers working with SMEs. It won the 2015 Civil Service Award for Programme Delivery Excellence.

What stayed behind was a way of taking gate decisions that the accounting officer and the centre of government could check for themselves.