Lord Callaghan: Offered advice

The then Home Secretary James Callaghan - now Lord Callaghan of Cardiff - told one cabinet meeting of the need to separate moderate opponents of the tour from the "more radical elements".

He said the so-called radicals "were believed to have been in touch with extremist coloured organisations".

The MCC finally called off the tour just days before the South Africans were due to arrive following intense behind-the-scenes pressure from the government.

Wilson had been desperate to see the tour scrapped after African and Asian nations threatened to boycott the Commonwealth Games that year in Edinburgh.

It sparked fears that they could be left with a "whites only" games.

Activist: Peter Hain was against the South African tour

Nevertheless, ministers were still deeply angered by the threatened campaign of violent protests and disruption by Hain and other leading anti-apartheid activists in the Stop the 70 Tour campaign.

Callaghan told a meeting of the cabinet on 30 April he intended to send a "firm reply" to a letter from Hain demanding assurances that the police would not adopt "discriminatory methods" in dealing with any protests.

Ministers agreed they must rebut any "insinuations" that the police would not be even-handed.

They went on to discuss pre-emptive legal action against Hain and other protest leaders which could have seen them sent to jail.

I am proud of my role in the campaign which, as Nelson Mandela later told me, delivered a decisive blow against apartheid

Peter Hain

The decision to abandon the tour was widely seen as a victory for Hain whose campaign had already demonstrated its willingness to break the law with a series of co-ordinated raids on cricket grounds which they daubed with slogans.

After the release of the report, Mr Hain said he was "both intrigued and amused" to hear the details of ministerial discussions of his youthful activities.

Harold Wilson: Ministers investigated Hain

He said: "This was classic non-violent direct action in the tradition of the Suffragettes and Mahatma Ghandi.

"I am proud of my role in the campaign which, as Nelson Mandela later told me, delivered a decisive blow against apartheid.

"Prosecuting me would have rebounded, because about 10,000 demonstrators were involved in the campaign.

"Later, I was the victim of a South African-financed private prosecution for conspiracy in 1972, and was acquitted."