Alistair Carmichael writes: for allowing mixed sex couples into civil partnerships

The late great Groucho Marx once said, "Marriage is a wonderful institution - but then, who wants to live in an institution?"

I have no problem in answering "I do" - coincidentally the same words I spoke on September 19th 1987 when my wife and I got married.

Like everyone else, our marriage has had its ups and downs but when we got married I had no doubt that it was the right thing to be doing and I have never doubted it for a second since. I like being married. For us, marriage is a good thing. In fact I would recommend it to anyone in a long term stable relationship and am still immensely proud of the role that our party played in dragging our country into the twenty-first century so that I can offer the recommendation to my friends in same sex relationships too.

That said, I realise that marriage is not for everyone. I know many people who are in long term relationships that are every bit as loving and as stable as our marriage but who remain unmarried. Some people are uncomfortable with its religious roots, some dislike the "baggage" that comes with it. Others may just have been a bit busy with other stuff, never found the right date or venue or dress or whatever.

Does this matter?

Yes, actually, it does. It matters because for centuries society has accorded special status to marriage. To be married opens the door to all sorts of rights and protections in law. These same rights and protections are also available to same sex couples who wish to register their relationship as a civil partnership but, irony of ironies, not to mixed sex couples. That is right - the law now offers a greater range of rights and opportunities to same sex couples than it does to mixed sex couples. That has got to be wrong.

One of the arguments advanced by opponents of equal marriage was that it "would change the nature of marriage". I thought it spurious at the time and nothing has changed my view since we accepted marriage equality.

What equal marriage did, however, was to change the nature of civil partnership - or, at least, how we saw it. To compensate for the lack of equality in marriage we constructed a ceremonial infrastructure around civil partnership to make it look like marriage and for a time we quietly ignored the fact that it was not as there was one main difference.

Marriage requires a public declaration of intent, a vow. Civil partnership does not.

Strictly speaking, civil partnerships can be entered into by rocking up at your local registry office with a couple of witnesses and registering your relationship. Thus those who register their relationship in this way can acquire all the rights and protections that come from being married.

So you can see the attraction for those who dislike what I refer to as "the baggage" that goes with marriage. Equal marriage was an enormous step forward, now we need to finish the job and extend the same equality to civil partnership.

A Scottish government consultation found that more than half of respondents wanted civil partnerships extended. The Isle of Man introduced different-sex civil partnerships this summer. Findings from the Office of National Statistics show that there are 3 million cohabiting different-sex couples in the UK and the number is rising fast. That means 1 in 5 households are a different-sex cohabiting couple: surely it is only a matter of time before the government has to realise that we cannot cling on to old traditions while the world around us changes.

But perhaps the biggest thing that has given me so much hope is the news that prompted me to write this post. In 2015 Rebecca Steinfeld and Charles Keidan, a London couple, took the government to court over its refusal to allow different sex couples the right to get a civil partnership. Though their case was rejected at the first stage, their appeal is being heard this November and I understand their legal team remain optimistic of winning. Should they succeed in getting a ruling that the ban on different-sex civil partnerships is unlawful I can't imagine the government will be slow-footed in lifting that ban.

Even if they do not win Charles and Rebecca's case has already captured the support and attention of a vast swathe of people inside and outside of Westminster. Politicians from all parties support the campaign set up in their honour - the Equal Civil Partnerships Campaign - and over 70,000 people have signed a petition backing their cause.

Change is on its way. Just like in 2013 I want the Liberal Democrats to lead that change. I hope that you will join me in supporting Charles and Rebecca in their campaign and pursuing all the legislative means possible to finish the job we started three years ago.

* Alistair Carmichael is the MP for Orkney and Shetland and Liberal Democrat Home Affairs spokesperson