A campaigner from Brighton was among people who demonstrated in London against Robert Mugabe's crackdown on political protests in Zimbabwe.

They chanted "liberate Zimbabwe" after Ghana's President John Agyekum Kufuor attended a meeting yesterday as part of celebrations to mark the 50th anniversary of Ghana's independence.

Protester Alois Mbawara, 25, from Brighton, of the group Free-Zim Youth, said he had disrupted the president's address to the gathering.

He said: "I went on to the stage to make my protests.

"We have been driven to ambush them because diplomatic means are not working.

"The president is also president of the African Union and we need them to put pressure on Mugabe.

"They're not doing anything, we still haven't heard what they think about the latest crackdown and the injuries to opposition leader Morgan Tsvangirai."

Mr Mbawara said Free-Zim Youth was a "radical and militant pressure group" but did not favour violence.

He said: "We are going to keep up this militant pressure on African leaders who are betraying the revolution."