Charles Moore is the former editor of the UK's The Daily Telegraph, The Sunday Telegraph and The Spectator. He writes in The Telegraph:

For the entire history of civilisation, marriage has been defined as being between a man and a woman. Throughout that history, almost all civilisations have regarded marriage as central to their survival.

So if you say that marriage should, in fact, be differently defined, you are saying something very big and bold. The onus of proof should surely not be on those who justify the status quo, but on you. You must show that you are right and that everyone else, for thousands of years, has been wrong.

One hopes that the Coalition can make a go of government in these difficult times. One understands why each partner needs to find issues that it can concede to the other. One also understands why David Cameron wishes to “rebrand” his Conservative Party. But can one feel completely easy when, driven by his political civil partnership with Nick Clegg, he tries to change the nature of marriage for ever?