The Crown Prosecution Service has confirmed Kent Police has now passed it a file on allegations concerning Conservative election expenses in South Thanet in 2015.

Kent Police had met the CPS for a discussion over the inquiry in March but at that stage did not present any formal dossier.

The CPS, which says it received the file recently, will now review the evidence before deciding whether any charges should be brought.

It has until early June to do so under election regulations that mean any decisions on charges must be brought within 12 months of an inquiry starting.

The timing could mean that a decision may come at the height of the general election campaign.

The allegations concern claims that the Conservative party failed to properly report its election expenditure in the campaign in South Thanet.

Had it done so, legal limits on how much parties can spend locally on campaigns would have been breached.

The Conservative party has denied any wrong-doing and recently the MP Craig Mackinlay reiterated that he believed all the expenses claims made by the party complied with the regulations.

He was interviewed under caution by Kent Police as part of the inquiry, with reports that he was interviewed for six hours.

In an interview for KMTV’s Paul on Politics show, he shrugged off the suggestion the inquiry would overshadow the Conservative campaign.

“I have done nothing wrong and acted honestly and properly throughout the campaign so no, I'm not concerned at all,” he said.

It has been claimed that hotel and the costs of battle buses used during what was a bitter battle between Mr Mackinlay and former Ukip leader Nigel Farage, may have been recorded as national expenses rather than local to keep spending within limits.

In particular, it has been claimed that hotel expenses totalling more than £18,000 were local expenditure rather than national but the Conservatives recorded it as the latter.

The allegations came as a result of an investigation by Channel 4 news, which also made similar claims about a number of other constituencies.

The CPS says it has been passed files by several forces involving allegations against 30 people.

The Conservative Party was recently fined a record £70,000 for irregularities in its election expenses - including money spent fighting for South Thanet.

A separate investigation conducted by the Electoral Commission, the election watchdog, concluded that there were significant failures by the party to report accurately how much it spent campaigning at three by-elections in 2014 and at the 2015 UK Parliamentary general election.