Labour leader says walkouts in support of workers from another industry are legal in most countries and should be so in UK

Jeremy Corbyn has said he would repeal legislation introduced by Margaret Thatcher that outlawed “sympathy strikes”, in which workers joined a picket line to support colleagues from another industry.

The ban was brought in by the Conservatives in the 1980s as part of moves to seriously weaken trade union powers.

When asked during interview on the BBC’s Andrew Marr Show on Sunday about his position on sympathy strikes, Corbyn said: “Sympathy action is legal in most other countries. It should also be legal here.”

The Labour leader was also asked about the return of flying pickets, in which workers turn up to support strikes at different locations around the country. “‘Flying pickets’ was a term that was first used in 1972. It was merely people moving around showing support during a very difficult industrial dispute,” he said. “We have to look at the question not of what trade unions are forced to do ultimately, but the causes of the problems in the first place.”

On whether that meant he would repeal the legislation imposing bans on these measures, he said: “Of course.”

His position is in direct opposition to the Labour 1997 manifesto of Tony Blair, which said: “We make it clear that there will be no return to flying pickets, secondary [sympathy] action, strikes with no ballots or the trade union law of the 1970s.”

Corbyn said he thought there should be “reasonable accommodation” with Argentina over the Falkland Islands, and there must be a “route through” to Islamic State to help bring about an end to the conflict in Syria, pointing out that governments in the region were already in touch with the group.

Len McCluskey, the general secretary of Unite, backed the idea of reversing some strike legislation.“What Jeremy was saying and what I’m saying is we need an industrial relations policy, strategy and climate for the 21st century. Many of the things Jeremy said … these union laws that restrict British workers are the worst in the whole of western Europe. How can it be fair that is the case?” he told the BBC programme Pienaar’s Politics.

But he said Corbyn was not suggesting, for example, tube drivers going out in support of striking workers in another industry.

McCluskey said he thought Corbyn’s interview was “absolutely first class” and the Labour leader was “on the side of ordinary working people in our nation”.

However, the nature of Marr’s questioning of Corbyn was attacked by John Prescott, the Labour peer and former deputy prime minister, who said it was a “disgrace”.

Lord Prescott said: “Here’s someone who is leading the debate by putting housing, social justice and equality right at the heart of our politics. And how did Marr respond? By asking questions to get answers he hopes will be in tomorrow’s Daily Mail.

“Why did he ask about flying pickets and the Falkland Islands? Are these really the big issues of today? Forget Deutschland 83, today’s Corbyn interview was more Marr 82.”