Richard Leonard is confident that Scottish Labour will decide today to officially support a referendum on any Brexit deal and campaign to remain in the EU.

The party’s executive committee is due to meet in Glasgow to determine its policy on Brexit following calls from Mr Leonard to commit to a confirmatory vote on any deal to leave the European Union.

Ahead of the meeting, a source close to the leader said: “Scottish Labour will back a confirmatory vote on any Brexit deal with a Remain option on the ballot paper.

“The party will wholeheartedly fight for a Remain victory in such a vote, with Richard playing a leading role in the campaign.

“Only Scottish Labour is building a radical platform of investment for our people, communities and public services.”

Pressure mounted for Labour to clarify its position on Brexit following a poor showing at the European elections, which saw the party slump to fifth place with just 9.3% of the vote, lose both its MEPs and caused two frontbenchers to resign.

Approximately 62% of Scottish voters backed Remain-supporting parties in the poll, won in Scotland by the SNP with 37.8% of the vote.

On the day after the results were announced, Neil Findlay MSP – an ally of Mr Leonard – announced that he was stepping down as the Labour’s Brexit spokesman due to party infighting.

He was followed by justice spokesman Daniel Johnson, who blamed “the current direction and leadership of the party”.

A defiant Mr Leonard said that he would not stand down following his party’s worst-ever showing in European elections, and, following a Labour group meeting in the Scottish Parliament, said: “There is a determination in the group to find a constructive way forward.

“We recognise that 9% is an incredibly bad result but we need to come together to build a way from that.

“I am taking the flak, and I am prepared to take the flak, for what was a poor result.

“Sometimes when your back’s against the wall, people come together.

“We need to rebuild the Labour vote but we will do that by being united.”

Speaking to the Press Association, he argued that the “change in circumstances” following the election had led him to conclude that a confirmatory vote must be held.

Mr Leonard added: “The circumstances, I think, lead me to the conclusion — and I hope that this will become the adopted position of the Scottish Labour Party — that we will support, under all circumstances, a confirmatory referendum on any deal and that confirmatory referendum should also give people the option of voting to remain.”