Most Labour MPs thought Jeremy Corbyn would lead them to annihilation at the General Election, shadow home secretary Diane Abbott has said.
Addressing a conference of Labour's Blairite grouping Progress, Ms Abbott said the "distraught" predictions had been proved wrong.
"The Parliamentary Labour Party, before we went into the General Election, were a very distraught set of people.
"They believed that Jeremy would lead us to annihilation; they believed, most of them, that nobody with a majority under 5,000 had a chance of coming back, and it was very sad in those final days and hours.
"But, as we now know, we won 40% of the vote. I was very struck that, on the first day back in Parliament, on the Tory side they were the ones that looked distraught, unhappy, divided."
Ms Abbott said the General Election manifesto had not been perfect but it did unite the party, and that spirit needed to be built on so that Labour could return to government in the next 18 months.
The shadow home secretary insisted that Labour would not win back key voters by moving to the right on immigration.
Ms Abbott said she would continue to "resist" attempts to shift the party's stance on migration rightward because: "Some of the thinking and ideas about immigration makes no economic sense, makes no moral sense, and doesn't fit with the values of the Labour Party."
Mr Corbyn posted a photograph of himself and festival staff on Twitter.
He tweeted: "Just arrived at #Glastonbury. Met with staff who help make this brilliant festival happen. Looking forward to speaking on Pyramid Stage @ 4"