The Department for Environment, Food and Rural Affairs (DEFRA) have done little more than police farmers to ensure they are doing what the EU tells them to do and administer the subsidy system ever since responsibility for farming and environmental policy was handed over to the EU many years ago. DEFRA - or whatever replaces it - will need to grow significantly when the UK regains control of farming, environment and fisheries and that growth should be outside of London.
The case for rebuilding DEFRA outside of London is possibly the strongest of all British government departments. Anyone who's been to the home of the civil service in Whitehall will have noticed a distinct lack of fields and livestock in the immediate vicinity. Whilst living and working in a city of 9m people doesn't preclude you from holding the necessary qualifications, it does result in a detachment from the reality of rural life which should be a pretty key requirement from policy makes in that department.
Locating the newly rebuilt DEFRA or is successor somewhere like Great Yarmouth or Felixstowe on the east coast would expose policy makers to the consequences of the decisions they make as well as providing some welcome investment in local and regional infrastructure in East Anglia, for example.
If proven successful, the Department for Transport should follow the decentralisation blueprint. London is the worst place to put anyone responsible for national transport policy because public transport in London is like nothing else in England. It gives ministers and civil servants a severely distorted view of how public transport works (or more often than not, doesn't) and leads to the kind of decisions that penalise people who rely on their own vehicles. Locating the DfT outside a metropolitan area would help make transport policy work for everyone, not just the privileged minority who live in large, well-connected cities.
UKIP has long championed localism and Brexit provides a perfect opportunity to deliver that change.