The Boy Scouts of America are preparing to go to court for a legal battle against the city of Philadelphia over their ban on gay members and staff.

The local scouting council currently occupies city premises rent-free but its ban on gays violates a city non-discrimination order.

Opening statements have begun in a civil jury trial and the case is expected to centre around a 2000 Supreme Court ruling that scouts and other private groups can limit membership.

The Cradle of Liberty Council of the Boy Scouts, which represents 87,000 scouts, complains it has been subjected to “unconstitutional coercion by the city”.

It was given the option of paying $200,000 a year to lease the building or to vacate it after 80 years of residency.

The Boy Scouts say they do not ask members to reveal their sexuality but require that they should be “morally straight and clean in thought, word, and deed”.

Boys are usually aged between ten and 11 when they join the organisation, and are expected to take leadership positions as they grow older.