The fall is in marked contrast with the previous three years. Thomson Reuters say: 'This follows a substantial increase in expenditure over the preceding three years, partly driven by the legal costs of restructuring public sector service provision during the post-2010 austerity cuts, such as those created by setting up joint ventures for shared services, and agreeing complex outsourcing arrangements.'

Highest spends in London boroughs

The research data shows that while that the average local authority spent £360,000 on external law firms in 2013/14, that was considerably outstripped by the UK’s Unitary Authorities, which each spent an average of £561,000, and London Boroughs, which each spent an average of £753,000.