FIVE parties, including the Conservatives and Labour, are under investigation after filing potentially inaccurate paperwork about their spending in last year’s general election.

The Electoral Commission made the announcement as it published its final spending figures for the snap poll, in which parties and campaigners spent more than £40m.

It said the Tories, Labour and Green Party were under investigation for submitting spending returns with missing invoices and for submitting “potentially inaccurate” payment statements.

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In addition, the Tories and Liberal Democrats were under investigation for making multiple payments to suppliers outwith the legally defined timeframes.

While the Women’s Equality Party was under investigation for submitting a spending return that was “inconsistent with its donation reports covering the same period”.

Two non-party campaigners are also under investigation.

The Commission said it has been necessary “to liaise with a number of parties and non-party campaigners to obtain additional information” and to open probes to determine the extent of compliance with electoral law.

It said these would examine whether rules were broken, and if they were, appropriate sanctions would be imposed.

After the 2015 general election, the LibDems were fined £20,000 for omitting 307 payments totalling £184,676 from the party's spending return.

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The official 2017 figures for large campaigners - those spending more than £250,000 - cover the 12 months leading up to the election on June 8.

As Theresa May only called the election on April 21, they include some general spending before an election was even contemplated.

Overall, the Tories spent £18.6m only to lose their Commons majority, while Labour spent £11m, the LibDems £6.8m, the SNP £1.6m, the Greens £299,352, the Women’s Equality Party £285,662, and - in a sign of their post-Brexit vote decline - Ukip £273,104.

The Best for Britain Campaign spent £353,118 - it is under investigation for submitting a spending return with missing invoices and for not returning an impermissible donation of £25,000 within the 30 days required by law.

While the National Union of Teachers spent £326,306, and is under investigation for submitting a spending return missing one invoice.

The 2017 figures show the Tories, LibDems and SNP all spent more in 2017 than in the 2015 election, while Labour, the Greens and Ukip spent less, Ukip massively so.

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In 2015, the Tories spent £15.6m, Labour £12m, the LibDems £3.5m, Ukip £2.85m, the SNP £1.48m and the Green Party £1.13m.

Bob Posner, the Commission’s Director of Political Finance and Regulation & Legal Counsel, said: “It is vital that voters are given an opportunity to see accurate and full reportable data on what parties and campaigners spent money on in order to influence them at last year’s general election.

“This provides transparency in the political finance system and is open for anyone to scrutinise.

“We are investigating possible breaches of the rules. However, our ongoing discussions with the major parties indicate to us that they may wish to consider the robustness of their internal governance and level of resourcing to ensure they can deliver what the law requires.”

The Commission said that, taking into account last November’s publication of political parties and non-party campaigners which spent below £250,000, the total reported spend by 75 parties and 18 non-party campaigners was £41,587,450 at the 2017 general election.

At the 2015 election it was £39,023,564 by 57 parties and 23 non-party campaigners.