Election fraud: Former Tory treasurer still under investigation by Met Police

Mr Day was referred to the Metropolitan Police earlier this year on suspicion of 'knowingly or recklessly making a false declaration would be an offence' by the Electoral Commission

The investigation centred on claims that the party electoral spending rules when it sent its 'battlebus' around marginal constituencies. (Getty)

A police investigation is still ongoing into the former Conservative party treasurer Simon Day concerning the party's spending at the last general election.

Mr Day was referred to the Metropolitan Police by the Electoral Commission earlier this year on suspicion of “knowingly or recklessly" making a false declaration of accuracy.

Earlier this year the electoral watchdog fined the party £70,000 for “numerous failures” in their reporting of expenses for the 2015 general election. Under election laws both candidates and their parties have to declare all campaign spending and a strict spending limit prevents more financially advantaged parties gaining an unfair upper-hand.

The investigation centred on claims that the party electoral spending rules when it sent its “battlebus” around marginal constituencies. Police investigated whether the cost should have been declared against local rather than national spending limits.

It comes after the Crown Prosecution Service announced on Friday that Craig Mackinlay, a Conservative fighting to retain his seat in the general election, was charged with electoral fraud as part of a major investigation into electoral expenses.

The CPS's statement said Mr Mackinlay, 50, is accused of “falsely” declaring expenses in the run up to the vote, which saw him narrowly defeat Ukip's Nigel Farage.

Allegations were made against a string of Tories after the election two years ago, relating to claims that incorrect expenses were filed for the party’s battle bus tour, but most had been dropped by the CPS up to now.

Announcing charges would be made against Mr Mackinlay, CPS head of special crime Nick Vamos said: “On 18 April we received a file of evidence from Kent Police concerning allegations relating to Conservative Party expenditure during the 2015 general election campaign.

“We then asked for additional enquiries to be made in advance of the 11 June statutory time limit by when any charges needed to be authorised.

“Those enquiries have now been completed and we have considered the evidence in accordance with the Code for Crown Prosecutors. We have concluded there is sufficient evidence and it is in the public interest to authorise charges against three people.”

Following the CPS's new announcement on Friday, a Conservative Party spokesman said: “We continue to believe that this remaining allegation is unfounded. Our candidate has made clear that there was no intention by him or his campaigners to engage in any inappropriate activity.

“We believe that they have done nothing wrong, and we are confident that this will be proven as the matter progresses. The individuals remain innocent unless otherwise proven guilty in a court of law.”