The rally outside the House of Lords, to coincide with the debate on the Marriage (Same Sex Couples) Bill, is the latest big lobby in support of marriage equality.
It is the continuation of a 21-year-long campaign that began way back on 1992 when the LGBT rights group OutRage! made the first challenge to the ban on same-sex marriage. Five lesbian and gay couples filed applications for marriage licences at Westminster register office. All were refused. But the campaign continued and was reignited with the formation of the Equal Love campaign in 2010, which kicked off the current push for equal marriage.
The House of Lords debate is on Monday and Tuesday, with a vote expected late on Tuesday afternoon. It is uncertain how the Lords will vote. We don't know the extent of the opposition. It would be a big mistake to assume that equal marriage is a done deal.
Lord Dear has predicted that the bill could be defeated by peers.
While it would be unusual and unethical for the unelected Lords to overturn a bill passed by a huge majority in the elected House of Commons, it is not impossible or unlawful. In the event of defeat in the Lords, it is not clear whether the government would invoke the Parliament Act to secure the bill's passage.
This is no time for complacency. Church leaders and right-wing peers are determined to derail the Marriage (Same Sex Couples) Bill. They plan to introduce a wrecking amendment, arguing that equal marriage has little public support.
Nonsense. Contrary to what the opponents of same-sex marriage claim, same-sex marriage has one of the highest public approval ratings of any government policy for many years.
According to a YouGov poll, 71% of the public, including 58% of religious people, believe same-sex couples should be permitted to get married in civil ceremonies in register offices.
Populus and ICM polls respectively recorded 65% and 62% public support for equal civil marriage.
The ICM poll found that 57% of people intending to vote Conservative at the next election support marriage equality.
The religious and political opponents of same-sex marriage are an increasingly small and shrill minority who are out of touch with the tolerant, liberal-minded majority. Their stand against marriage equality fuels homophobia and gives comfort to bigots everywhere.
They say they're not homophobic but a person who opposes gay equality is homophobic in the same way that a person who opposes black equality is racist.
Denying same-sex couples the right to marry disparages and insults their love. It sends the message that LGBT couples are unfit and unworthy.
The critics of same-sex marriage want us to remain second class citizens, banned by law from marrying the person we love. In contrast to their intolerance, we affirm love and equality for everyone.
The legislation before the House of Lords seeks to ensure equal marriage rights for all. In a democratic society, everyone should be equal before the law.
Regardless of whether people agree with homosexuality or matrimony, the ban on same-sex marriage is homophobic discrimination and should be repealed.
We are on the cusp of ending the last major legal discrimination against LGBT people in the UK. The vote for equal marriage is the culmination of the struggle for homosexual equality that I and many others began in the 1960s. We are nearly there. Fingers crossed!
For more information about Peter Tatchell's human rights campaigns: www.PeterTatchell.net