TORY candidate Craig Mackinlay has been charged for overspending on expenses in the 2015 general election. Mackinlay, who is standing again to be the MP for South Thanet, has denied wrongdoing.

The Prime Minister has taken the unusual step of commenting on what is a a live case, saying she stood by her candidate – who will appear at Westminster Magistrates’ Court on July 4 – and that the charges were “unfounded.”

The race for South Thanet was one of the most heated in the last general election, with Ukip’s Nigel Farage desperately trying to get elected.

The Tories threw everything at the seat. Their battle bus, packed full with young campaigners, made several stops in the constituency.

Complex election spending rules mean parties must disclose national spending separately from funds used to promote individual candidates.

There are limits on what can be spent locally and nationally.

Mackinlay filed expenses of £14,800, just under the legal constituency spending limit.

But those activists who were bussed in were declared as national spending, as they went all over the country.

Other party staff based themselves in the constituency for the campaign.

Nick Timothy, one of May’s chiefs of staff, stayed locally in a hotel.

The party say he was working on national campaigning, and therefore his spending, including hotel bills should be declared nationally.

Police were asked to investigate claims the Tories spent more locally than they declared. Around 20 seats visited by the bus of campaigners were also being investigated, but the CPS dropped the case last month.

Mackinlay, his election agent Nathan Gray and party activist Marion Little, have been accused under the Representation of the People Act 1983 by the Crown Prosecution Service. Reports yesterday suggested they could spend a year in prison if found guilty.

Prime Minister Theresa May said: “The Conservative Party continues to believe that these allegations are unfounded. Craig Mackinlay is innocent until proven guilty and he remains our candidate.”

A statement on Mackinlay’s Facebook page said: “My candidature in South Thanet is entirely unaffected and my campaign continues as before. I have done nothing wrong and acted honestly and properly whilst a candidate in 2015, as all candidates do, [and] acted upon advice throughout.”

Mackinlay said it was a “shocking decision” by the CPS. He added: “I am very disappointed with the way this has been handled by the CPS and Kent Police and I must question the timing of this decision given that Kent Police confirmed on April 18 that their file had been sent to the CPS to review and make their decision. Why leave this until a few days before the election?”

Labour leader Jeremy Corbyn said May saying Mackinlay was “innocent” could be seen as “interference” in an independent process.

He said: “Nobody should be commenting on the details of an ongoing case. The police must be allowed to act independently, to investigate on the basis of any evidence they’ve got and the Crown Prosecution Service must be allowed to make its decision on whether to proceed on a case.”

The SNP’s Pete Wishart said the Tories should have suspended the candidate while the legal action takes it course. “A Tory candidate/former MP has been charged for electoral fraud and is still standing. The Tories couldn’t care less about our electoral laws,” Wishart said.