Labour's U-turn on equal marriage: why is equality for minority groups a matter of conscience?

After a “passionate” meeting of the Shadow Cabinet yesterday, it seems likely that Labour will not impose a three-line whip on equal marriage proposals, allowing MPs to vote on the basis of conscience.

It represents a backtrack on the part of the Labour leadership, which recently made it clear such a whip was "highly likely".

Apparently the U-turn was not proposed by members of the Shadow Cabinet on a matter of principle, but largely because three shadow ministers - including Stephen Timms and Gavin Shuker - had threatened to resign. Three Shadow Cabinet ministers - Angela Eagle, Stephen Twigg (both gay) and deputy leader Harriet Harman had argued passionately in favour of maintaining the line.

Some senior Labour figures had argued that this would not have happened in the past. Despite the many disappointments and betrayals of New Labour, its record on pushing through LGBT equality laws was exemplary. Votes on key equality issues such as the repeal of Thatcher's Section 28 were whipped votes - and that was at a time when homophobia was far more entrenched.

It might be asked what all the fuss is about. The overwhelming majority of Labour MPs will vote in favour of equal marriage, after all; and wouldn't a free vote have more legitimacy?

But the reason for the mounting and justifiable anger within Labour's own ranks is that the party should not be making an issue of equality and civil rights a question of conscience, but rather one of principle. It should go to the heart of what Labour is all about, after all. The Liberal Democrats will impose such a whip, allowing them to claim Labour's mantle on gay equality. The argument about the questionable commitment to gay equality within the Conservatives' own ranks will be lost. The handful of anti-equality Labour rebels would still vote against if there is a whipped vote, but at least the party would have been able to claim a principled and unwavering commitment to equality.

After all, whipped votes are standard practice. Granting a free vote on equal marriage makes it an exception. If equality for minority groups is a matter of conscience, why not NHS spending, devastating cuts or saddling students with a lifetime of debt?

It may also prove rather more difficult to get equal marriage through the House of Lords - and harder still if Labour do not impose a whip.

The growing debacle has not been helped by comments from backbencher Austin Mitchell - previously embroiled in a storm over alleged sexism - who described gay marriage as "neither urgent nor important," causing fury on Twitter.

As well as looking like weakness on the part of the Labour leadership, a rebellion is uniting otherwise disparate factions of the party. The left has been joined by leading Blairites, such as Richard Angell - deputy director of arch-New Labour faction Progress - and former NUS President Wes Streeting. Some activists are even threatening to resign over the issue.

Labour's leaders face making a totally unnecessary mess out of what should have been a straightforward affirmation of equality. Instead of leaving it up to individual MPs, they could distinguish themselves from the Conservative leadership by making it clear equal marriage is the official position of the party. Now they face a totally avoidable backlash within their own ranks. What a cock-up.

To read more about our Independent Voices Equal Partners campaign and sign the petition to back equal marriage, click here.