“It is an offence to knowingly make a false declaration. In order to bring a charge, it must be proved that a suspect knew the return was inaccurate and acted dishonestly in signing the declaration.

“Although there is evidence to suggest the returns may have been inaccurate, there is insufficient evidence to prove to the criminal standard that any candidate or agent was dishonest.”

The Conservatives have already admitted under-declaring spending on their national 2015 campaign and were fined £70,000 as a result, but they insist all local spending was properly declared.

Source: Tory election spending: CPS announces it will not charge Conservative candidates amid campaign spending allegations | The Independent