A Scottish Catholic bishop has condemned the Green Party for expelling one of its councillors for breaking rank over the issue of marriage rights for same-sex couples.

Earlier this month, Councillor Christina Summers was forced to leave the Green group on Brighton and Hove City Council following an internal investigation by the party.

Ms Summers went against party lines in August when the Greens were discussing the government’s plans to introduce equal marriage by 2015.

During a Brighton and Hove City Council debate on 19 July, Ms Summers said: “When you touch marriage, you’re touching family, and you’re hitting at the very heart of God, and I have an enormous problem with that”.

Bishop Joseph Devine accused the party of “masquerading” as an environmentalist organisation and in a statement criticised Scottish leader Patrick Harvie, saying:

“In Scotland there is a perception that its leader seems more determined to promote and champion the “gay” agenda rather than explain and contribute to the debate on environmental issues.

“To seek to coerce loyalty to the party above loyalty to individual conscience calls to mind the worst kind of totalitarian politics.”

In response, Mr Harvie told the BBC: “People like Bishop Devine need to catch up with the fact society has moved on from the days of homophobia in politics.

“The only parties that espouse the kind of views about LGBT rights that Bishop Devine has are the BNP and UKIP.”

He added: “I find the comments slightly absurd. If you look at the track record of Green parties around the world, you see a very clear, consistent, strong, environmental, economic and social justice agenda.

“To suggest that because we support gay rights we are not promoting green economics or green politics is nonsense.”

Bishop Devine has also been condemned by pro-choice campaigners after he made comparisons between images of Nazi death camps and abortion.

He was responding to the case of two Christian campaigners who held up banners of aborted foetuses at a Brighton clinic.

According to the Argus newspaper, Councillor Summers has previously taken part in an anti-abortion vigil in the city.