A misleading BBC News graphic that claimed pro-Brexit parties lost at the European Election was a 'lapse of editorial standards', the broadcaster has admitted.

The Corporation reported on its website in May that Remain parties had won 40.4 per cent of the vote.

It included votes from the Liberal Democracts, Green Party, SNP, Change UK and Plaid Cymru to arrive at that figure.

But its tally of pro-Brexit parties came to just 34.9 per cent because it only included the Brexit Party and UKIP, and excluded the Conservative Party.

The misleading BBC News graphic that claimed pro-Brexit parties lost at the European elections failed to count the Tories in the Leave group

Had the Tories been considered a pro-Brexit party, Brexiteers would have outperformed Remain parties by more than three per cent.

The BBC's complaints unit twice 'rebuffed' the complaint before it was eventually upheld, according to Guido Fawkes.

The graph has now been removed from the online story and a correction note has been issued.

BBC News said the graphic was an attempt to 'illustrate the squeeze on Labour and the Conservatives by parties offering a clear cut proposition on whether the UK should leave or remain in the EU'.

In a leaked email, Dominic Groves, BBC's complaints unit deputy head, said the graph was an effort 'to provide some clarity' at a time when both sides of the Brexit argument were claiming the results at the European elections favoured them.

Groves wrote to the complainant: 'We think this a reasonable approach in principle, but the resulting graphic does not seem to us to have contained sufficient information to achieve the desired result.

The nationwide vote in May saw Nigel Farage’s newly launched Brexit Party take 29 of the 73 available seats

'The bar labelled 'pro-Brexit', as you have pointed out, reflected only the combined vote for the Brexit Party and UKIP.

'Those were the parties either advocating a no-deal Brexit or explicitly willing to countenance it – but those are not the only 'pro-Brexit' positions, and a significant section, if not a majority of the Conservative Party is in favour of a form of Brexit, whatever the actual balance of opinions in it.'

He later added that there had been a 'lapse of editorial standards' and that the complaints unit would 'consider what further action is required'.

A BBC spokesperson said: 'We note the findings of the ruling.'

The nationwide vote in May saw Nigel Farage’s newly launched Brexit Party take 29 of the 73 available seats at the European Elections.

The Liberal Democrats came in second place, scooping 14 seats, while Labour and the Tories won a combined 13 seats.