"We also call upon the Palestinians themselves to return to unity in the context of a recognised Palestinian legal structure, and in this way to spare the people the continuing and degrading siege, " Archbishop Twal added.

BBC: Pope 'to visit Holy Land in May'

Chris Fry, managing partner at Unity Law, who is conducting the campaigners' legal case, said the centre was due to close on 1 May and he feared both the facilities and staff would be dispersed.

BBC: Stocksbridge Leisure Centre decision deferred by court

"If people can be made legal, they can contribute to the country, and there will be unity in the country, " she said.

BBC: Trafalgar Square rally