Tamil protesters are staging a demonstration outside the Mansion House in the City of London.
The Sri Lankan President Mahinda Rajapaksa had been due to address a Diamond Jubilee Commonwealth Economic Forum, but the morning session of the event has now been cancelled.
The protesters accuse Rajapaksa of running a dictatorial regime which represses the Tamil people.
A spokesman for Tamil Solidarity said:
"This butcher and his dictatorial regime is still brutally repressing the Tamil-speaking people and trampling democratic rights. Britain has enough war criminals without Rajapaksa, with the blood of hundreds of thousands on his hands, 40,000 in the last weeks of the war alone, being invited for the Jubilee."
More top news
Della Callagher died and 32 other diners became seriously ill after eating the poisonous yuletide meal.
The ex-Tory MP's rant was secretly recorded on the driver's phone and published in The Sun.
You dash to the platform, desperate to get home but find out you've got a few minutes to spare before the next Tube. What do you do?