BOB Stewart has confirmed he will oppose gay marriage on a "point of principle" when the controversial vote reaches Parliament next year.
The Beckenham MP says, despite having grown to accept civil partnerships, he continues to oppose gay people having a formal marriage ceremony and has written to the Prime Minister David Cameron to inform him of his views.
More than 110 of the 303 Conservative MPs are thought to be planning to oppose the bill in what could be the biggest Tory rebellion of modern times.
It will be a free vote, meaning MPs are allowed to vote as they wish and not as directed by party managers.
Mr Stewart said: "To me marriage is a sacrament and, by definition, religion and tradition, a union between a man and a woman.
"As such, I view marriage, whether organised simply by the state or a combination of church, temple, mosque and state, to be different to civil partnerships and special in a unique way.
"Personally I am not in the least homophobic and have great and true friends who are gay."
He said: "I accept civil partnerships now although I must admit that I was vehemently against them when I was a young man. Of course we lived in different times then and society has changed - me with it.
"On a point of principle I have informed the government that, should there be a vote in the House of Commons asking MPs to vote in favour of so-called gay marriages, I will not support the idea. I have also signed the Coalition for Marriage petition."
The former British Army Officer, who became an MP in 2010, added: "I have informed the Prime Minister, in written form and properly through the Chief Whip that I will not be supporting or voting for it under any circumstance."