The City Hall in Belfast, Northern Ireland, was lit up in rainbow colours last night to coincide with the start of Pride, but it will be the only of the UK’s capital cities where same-sex couples will be banned from marrying once the law changes in Westminster and Edinburgh.

Last night,the House of Commons Speaker, John Bercow, told the audience of Amnesty’s annual Belfast Pride lecture that although Northern Ireland is “considerably behind” when it comes to LGBT rights, “if it’s won through in the rest of the Kingdom it will prevail in Northern Ireland”.

The House of Lords will resume its debates on same-sex marriage on Monday, with the measure expected to pass its third reading on the 15th July and be approved by both Houses of Parliament on the 16th or 17th July. This will only introduce same-sex marriage in England and Wales as marriage law is devolved to the Parliament in Scotland and the Assembly in Northern Ireland.

Scotland’s government has already published its own same-sex marriage bill, which more-or-less mirrors marriage equality in England and Wales.

Members of Northern Ireland’s Assembly have repeatedly blocked introducing same-sex marriage, which is opposed by the country’s First Minister, Peter Robinson. DUP’s MP Ian Paisley Jr previously said: “I am pretty repulsed by gay and lesbianism. I think it is wrong. I think that those people harm themselves and – without caring about it – harm society.”

Same-sex couples who marry in England, Wales or Scotland once the law changes, will be regarded as being in a civil partnership in Northern Ireland.

While gay male sexual activity was decriminalised in England and Wales in 1967, it was only made legal in Northern Ireland in 1982.

Polls show that the majority of people in Northern Ireland (57%) support equal marriage for same-sex couples.