See this write up in the Guardian
Incensed, as seems to be all too common a mood for me right now, I wrote him a letter.
Dear Lord Tebbit
I read your comments regarding gay marriage, and I have a couple of counter points to bring up.
1. The opinion of grass roots Tories is not the same as "what is social justice"?
2. Your arguments about marriage legislation leading to members of the same family marrying is what's known as a slippery slope fallacy - look it up. Essentially it's not implied by the legislation that these illegal marriages would be made legal, nor is anyone asking for that.
3. Your suggestion that gay marriage is a root to enable sham marriages for nefarious purposes somewhat misses the point. Gay people are asking for the same rights as non gay people when it comes to making a lifelong commitment.
I don't know whether you're ignorant of or bigoted against the people who stand to gain fairness from these laws. I recommend you have a long hard look at yourself before you vote.