Somerset, Norfolk and Lancashire county councils are exhibiting some of the warning signs demonstrated by Northamptonshire county council before it declared itself effectively bankrupt last month, according to the Bureau of Investigative Journalism.

The three join the Tory-run Surrey county council, which is facing a £100 million shortfall, as the counties in the deepest financial crises. The National Audit Office has found that one in ten councils could run out of money in the next three years. County councils have been hit hard by cuts to local government funding since 2010 and social care costs are rising.

Somerset, Norfolk and Lancashire’s usable reserves — effectively rainy day funds — have all fallen substantially in recent years, the bureau’s research found. Somerset’s usable reserves have fallen by 60 per cent in the past five years, Norfolk’s have halved and Lancashire’s have fallen by 48 per cent.

All three show further signs of financial difficulty. In Somerset the council overspent on children’s and adult’s social services in each of the past three years and its budget this year projects a £14.6 million overspend on children’s services, the largest in the country. Last month it announced plans to close two-thirds of its children’s centres.

In Norfolk the council has spent more than it budgeted for in each of the past three years, the bureau found, although the council disputed the claim it had been overspending and insisted its budgeting was “robust and prudent”.

Lancashire has overspent on children’s and adult social services in each of the past three years, and its funding gap is £97 million in the coming financial year.