Other groups, including the Church of England, the Roman Catholic Church and the orthodox Jewish organisation United Synagogue, also resisted the legislation, but they have not indicated that they will go as far as to surrender their marriage licences.

The Government has given repeated assurances that legal ­provisions should prevent anyone being forced to act against their religious teachings.

The warning comes in a letter to Sikh places of worship, known as gurdwaras, from Sikhs In England, a specialist advisory body.

It urges them to consider deregistering as a venue for civil weddings - which would leave gurdwaras performing wedding rites with no legal force.

Couples would have to attend a separate ceremony in a register office or other venue recognised by their local council.

Although the advice is not binding, it is understood that it is being taken seriously.

Lord Singh, the director of the Network of Sikh Organisations, told the House of Lords that he feared opponents of same-sex marriage would be "coerced" into accepting the new legal definition of marriage.

The network also advised members that it believes faith groups could end up being "bullied" into conducting same-sex marriages.

The same-sex marriage Act, which received Royal Assent this week, contains provisions to prevent individuals and groups from being compelled to carry out such unions, under a so-called "quadruple lock" of legal protections.

But Sikhs In England has told supporters that such assurances could be swept away by a challenge in Strasbourg. Harmander Singh, principal adviser to Sikhs In England, said: "We are concerned that the quadruple lock isn't going to be worth the paper it is written on.

"In the longer term, as soon as there is an issue and it goes to the European Court of Human Rights, no one can be sure, because the quadruple lock means nothing under subsidiarity."

In common with many churches, mosques and synagogues, gurdwaras are registered with councils as venues to conduct weddings.

It enables them to combine the civil formalities of the marriage with a religious ceremony.

If Sikh places of worship deregister, it would lead to a situation similar to that in France, where couples have a civil wedding at the town hall with a church service as an optional extra.

"We have no authority, neither has the Government, to change our scriptures," said Mr Singh. "We are bound by our religious teachings and we have been put in a difficult situation."

He added: "Civil marriage is, with respect, a paper exercise."

END