A state visit does not imply endorsement
Some of the blogosphere left are trying to say that the Saudi state visit implies the Government somehow doesn't care about the appalling human rights record of the Government there.
But I seem to recall state visits by Presidents of the USSR throughout the Cold War when both sides were condemning each other's political and economic systems, were pointing nuclear arsenals at each other and we were specifically condemning the Gulag and the treatment of dissidents.
My take on the Saudis is the same as that Churchill had on Stalin's Russia when the Nazis invaded it: "If Hitler invaded hell I would make at least a favorable reference to the devil in the House of Commons."
They are a ghastly regime but the current alternative - even more extreme Islamism of the al-Qaeda variety - is even worse.
It's the same reason the West correctly backed Saddam's Iraq against Iran.
Diplomacy sometimes involves sitting down and establishing common interests with people you would otherwise not want to invite to dinner. You have to do it if you have wider strategic interests that need protecting, or you just need to be in dialogue with your "enemy's enemy". Unfortunately it's part of being in government - unlike Vince Cable we can't indulge in gesture politics.
I'm fairly sure that vice versa the Saudis find it equally, if not more distasteful than we do sitting down to negotiate with decadent infidel Western liberals who have a female head of state.