The Labour Party must campaign for a second referendum to stop no-deal Brexit, a senior Labour frontbencher has said.

Shadow foreign secretary Emily Thornberry said she expected the party to have a set of “really bad results” in the European Parliament elections, and called for a change of direction from the leadership.

Speaking to BBC News, Ms Thornberry said: “I think we are going to get a kicking.

“I feel really sorry for all our MEPs who are going to lose their seats, all the candidates who work so hard and all our activists who, frankly, have not done well and it’s not their fault.

“I think that the point is that we went into an election where the most important issue was ‘what was our view on leaving the European Union’ and we were not clear about it.

“We were not clear on the one single thing that people wanted to hear and that wasn’t their fault.

“We sent people out to campaign on that and, unfortunately, we just weren’t clear enough.”

Ms Thornberry said: “I fear we will have no deal and we must be clear it will be a disaster for the country so we must have a second referendum.”

A Labour spokesperson said: “We ran a positive campaign attempting to bring our divided country together and to challenge the far-right in Britain and across Europe.”

Several Labour MPs tweeted messages of support after the shadow foreign secretary called on the party to explicitly support a second Brexit referendum and campaign to remain.

Former leadership candidate Owen Smith tweeted: “.@EmilyThornberry entirely right that @UKLabour should have been clear in these elections that we want a public vote on any deal – and that we would campaign to Remain. Of course, that should have been our policy for the last three years, as many of us have long argued.”

Chris Bryant tweeted: “Well done @EmilyThornberry telling it as it is. We cannot keep on trying to have two incomprehensible policies at the same time on Brexit.”

However, Caroline Flint offered a different view, tweeting: “Early warning. Doncaster turnout similar to 2014. Labour vote in Doncaster halved. Pro Brexit Parties not inc Tories up 10%. Brexit Party 45% of the vote. It would be a mistake for Labour to only become a Party for Remain/2ndRef voters.”

Earlier, shadow chancellor John McDonnell said he expected Labour to get “a good kicking” in the poll.

Mr McDonnell told Sky News: “I think we most probably will get a good kicking in the election results tonight.

“We’ll see. We are braced for that.”

He added: “But, you know, we had to do the responsible thing.

“It was a hard road to follow. But someone had to be there and say ‘Can we bring the country back together again?’

“And it would have been easy to go to one side, go to the Remain side and ignored all those people who voted Leave – that’s not the nature of our party.

“We are the party that is trying to bring people back together again.

“That’s been difficult electorally for us in these elections, of course, it has.

“But now we have got to move on.”

Labour Deputy Leader Tom Waston has called for the party to “find some backbone” and fully commit to a second referendum on Brexit to have any chance of winning the next general election.

Writing in The Observer, he said: “For our party’s sake, but most of all for Britain’s sake, Labour needs to find some backbone on Brexit, find our voice – and do it fast.”

He added: “Our performance (in the European elections) is a direct result of our mealy-mouthed backing for a public vote on Brexit when it is being demanded loud and clear by the overwhelming majority of our members and voters.

“Polls show Labour has been losing up to four times more voters to parties giving full backing to a people’s vote than to (Nigel) Farage.

“And those same polls show we would have beaten him by a country mile if we had unambiguously backed a public vote on any form of Brexit.

“Once results are in, we must channel our frustration into winning those voters back. Never again can Labour policy on the most crucial issue of our generation be on the wrong side of its members and voters.”