One of the most infuriating aspects of this year's general election isn't the spontaneity of it's calling or the fact that it appears to be a foregone conclusion, but the fact that that the outcome of the last one is still being investigated .

In March, the Electoral Commission slapped a £70,000 (GBP) fine on the Conservative Party for a variety of election spending infringements.

The party was accused of producing a spending return - a record of all that their candidates and national party spent - which was missing £104,765 worth of spending at the 2015 election.

This followed earlier fines of £20,000 for Labour and the Liberal Democrats respectively for similar misreporting of election spending returns.

The Crown Prosecution Service also stated it had been handed investigation files by 12 police forces.

Police have not named either the MPs nor the election agents under investigation, but races in up to 20 seats are believed to be under scrutiny.

There were 96 seats won by the Conservative Party in 2015 whose boundaries fall within the boundaries of the police force areas named by the CPS.

Questions of legitimacy

Dennis Skinner, MP for Bolsover, asked the prime minister if candidates and MPs under investigation with regards to election spending in 2015 would be banned from running.

Will the Prime Minister give a guarantee that no Tory MP who is under investigation by the police and the legal authorities over election expenses in the last general election will be a candidate in this election? If she will not accept that, this is the most squalid election campaign that has happened in my lifetime.

The prime minister responded.

I stand by all the Conservative MPs who are in this House and who will be out there standing again, campaigning for a Conservative Government who will give a brighter and better future for this country.

What seats could these include?

At present only 20 are believed to be under investigation.

One significant accusation was that campaign battle buses should have been counted in local candidate spending in individual seats, and not in the party's 'national campaign' spend.

If the buses and hotel bills for the riders of each bus were to be included in local candidate spending, it could push candidates over the limits set by electoral law, voiding their elections.