A marriage registrar has vowed to make a legal challenge to the acceptance of civil partnership ceremonies, claiming that she objects to them on religious grounds and should therefore be exempt from having to perform them.

The woman, who has not been named, is described as “a devout Christian”. She is taking action against Islington Council through an employment tribunal, after her stance escalated into a full-scale dispute with her employers.

Over 600 lesbian and gay couples have had their life partnerships solemnified in ceremonies in the North London borough since the law changed in 2005. However, the unnamed registrar has refused to take any part in them, reports This Is London news site.

The case is sure to be used in the continuing battle between opponents of equal rights, many of them conservative Christians, and civil and gay rights campaigners.

Equalities activists say that ‘conscience’ exemptions at work should be permitted, but should never be allowed to take priority over public access to services for others or the dignity of clients. Those with an objection to civil partnerships have the option of not working for agencies supporting them, they point out.

Other Christian groups, such as LGCM and Changing Attitude, have strongly supported civil partnerships, and say that any claim about a general Christian or religious objection is a misrepresentation of the diversity of opinion in faith communities.

When the Civil Partnership Act came into force just over a year ago, on 21 December 2005, Isington council celebrated it in style, naming the day Pink Wednesday and giving town hall staff pink buttonholes to wear as they served champagne to guests.

The move was also publicly backed by London Mayor Ken Livingstone.

More than 18,000 civil partnerships took place in Britain in 2006, with the numbers still thought to be rising.

Registering a civil partnership gives same-sex couples the same tax, employment and pension benefits as married heterosexual couples, but is not designated as marriage or a wedding.

The first gay couple to register and celebrate their partnership at Islington town hall were local council employees Viktoria Kingsley, from New Zealand, and Fiona Dunning, from Australia.