22 May 1970
In May 1970, the British government requested that the English Cricket Council reverse its decision to invite the South African cricket team on tour. This was as a result of the reaction caused by the all-White composition of the South African team among the anti-Apartheid activists and countries that were opposed to the Apartheid government of South Africa. For example, Peter Hain led a campaign called Stop the Seventy Tour. The campaign threatened to disrupt any matches played during the tour. African and Asian countries also threatened to boycott the Commonwealth Games that would be held in Edinburgh in the same year should the South African team be allowed to be a part of that tour. The English Cricket Council subsequently withdrew the invitation on 22 May 1970.
References

BBC, (1970), South Africa cricket tour called off, from BBC News, [online], Available at news.bbc.co.uk [Accessed: 17 May 2010]|Barclay, Theo, Playing With Apartheid: The 'Rebel' Cricket Tours to South Africa, from ThinkAfricaPress, [online], Available at thinkafricapress.com [Accessed: 20 May 2014]