NO CRIMINAL charges are to be brought against Conservative MPs or officials in relation to allegations of spending irregularities in the 2015 general election campaign, the Crown Prosecution Service has announced.

One file, relating to the victorious Tory candidate in Thanet South, Craig Mackinlay, remains under consideration.

But the CPS cautioned that this should not be taken as an indication of whether charges will be brought in this case, which was referred more recently than the others.

The CPS head of special crime Nick Vamos said that prosecutors considered files from 14 police forces, but determined that - while spending returns may have been inaccurate - there was insufficient evidence to prove that any candidate or agent was dishonest.

"We reviewed the files in accordance with the Code for Crown Prosecutors and have concluded the tests in the Code are not met and no criminal charges have been authorised," said Vamos.

Campaign spending by candidates during a general election is strictly controlled by election law.

During the "short campaign" - which begins once a candidate declares their intention to stand following the dissolution of Parliament and runs to polling day - all candidates can spend a fixed sum of £8,700.

This is then topped up by a variable amount depending on the size of the constituency.

In borough constituencies it is 6p for each registered elector, while candidates in county constituencies get an additional 9p per elector.

For a borough with 70,000 electors that would mean a maximum spend of £12,900, while in a county seat with the same number of electors the limit would be £15,000.

The limit covers any expenses incurred for the purposes of the candidate's election, including advertising, leaflets, accommodation, transport costs, and administrative expenses.

Spending by the national party in a constituency also counts towards the limit if it specifically promotes the local candidate, such as a leaflet or letter to voters introducing the candidate and their policies.

Items which promote the party, such as posters with the party name but not identifying the candidate, are not included and would count towards the party's national spending limit.

Candidates, or their agents, must submit their campaign spending returns to their local returning officer within 35 days of the election result being declared.