The Western Isles (Eilean Siar) are to become the only part of Britain to ban gay marriages after local councillors and registrars agreed to a boycott.

Registrars are permitted under the Civil Partnership Act to refuse to conduct a ceremony on moral grounds. But councillors in Stornoway have voted to force the Isles to become the only place in Britain with a blanket ban on all gay ceremonies.

The policy and finance committee of the Western Isles council ratified the decision: “it is a practical decision – our officers don’t want to do them so we didn’t even go into the debate (over morality),” explained Angus Campbell, the chairman of the committee.

Calum Irving, director of the gay rights charity Stonewall Scotland, claims that the ban flies in the face of the policy of the Scottish Executive: “I received an assurance from the Scottish Executive that any couple wishing to have a registration and ceremony in Scotland would receive one, so it is very concerning that the Western Isles have taken this stance.”

It is widely expected that should the council and its registrars refuse to allow a gay couple to wed that a case under the Human Rights Act would be brought against the local authority.

Over 150 gay couples are expected to tie the knot in ceremonies in Scotland on Tuesday. The first ceremonies will take place on Monday in Northern Ireland, Tuesday in Scotland and in England and Wales from Wednesday.