Marriage is a civil right.

UK lesbian couple denied marriage in London

This is great in a double-way. While civil partnerships in the UK are required to be equal to marriage, gay couples still can’t marry, so they’re still denied equality. If you think this is nitpicking on a principle thing, I have to say that making homosexual partnerships and heterosexual partnerships the same thing, asides from the romantic aspect of being married, also has legal implications: If it’s the same thing, you cannot change one thing without changing the other and that means that discrimination against either form of partnership becomes completely impossible. Of course it is also a moral principle issue – it’s discrimination. So yes – those couples should not be happy to live their partnership under a pseudo-name and they’re doing well going to court. I wish them the best of luck.

On a second part, four heterosexual couples will join the sueing because these couples want the civil partnership. It’s discriminatory towards them, too, to not grant them the same right for a civil partnership as a homosexual couple. All the more power to them for standing up for equality even though they can have the traditional, supposedly more desired legal bond and will, if any difference are made, probably end up with the better rights having a marriage. The best of luck to them, too!