Two protestors from Fathers 4 Justice have climbed onto the roof of Labour Deputy Leader Harriet Harman's south London home for the second time in a month, the campaign group said on Wednesday.

Scotland Yard said police were called at 6.22 a.m. and that officers had gone to the house in Herne Hill where they were in dialogue with the men.

A spokesman for Fathers 4 Justice said he believed the two were Mark Harris and Jolly Stanesby, who staged last month's roof-top sit-in.

Both men were arrested after that protest and are on police bail.

The group campaigns for divorced fathers to be given better access to their children and says it has been rebuffed in its attempts to meet Harman, who is minister for Women and Equality as well as Leader of the House of Commons.

Wednesday's protest is the latest in a line of high profile stunts by the group, which has included pelting then Prime Minister Tony Blair with condoms full of purple flour in the House of Commons debating chamber in 2006.