British lawmakers in the House of Commons voted overwhelmingly in favor of a bill proposing the legalization of same-sex marriage.

It's the first of several votes required for the UK's "marriage bill." If it becomes law, the legislation would enable same-sex couples to marry in both civil and religious ceremonies, as long as the religious institution consents.

"Today was about do we accept the fundamental principle of gay people being allowed to call their union a marriage. I'm glad that we do," British Labour Party MP Toby Perkins said.

"Marriage is a great institution and it should be there for people who are gay as well as people who aren't. That's why I've pioneered this change," Prime Minister David Cameron said.

The vote went Cameron's way, but it cost him popularity within his own party. More than half of his 303 conservative lawmakers voted against or abstained from voting for the bill.

"(For) many people, yes, it's a non-issue. But to a lot of people, they feel that this is the straw that has broken the camel's back," Geoffrey Vero, president of the Surrey Heath Conservatives, said.

"Who are we, who is this government, who is this country to determine, impose, nationalize a new definition of marriage, which will have huge implications?" British Conservative Party MP Tim Laughton charged.

Sir Gerald Howarth, another British Conservative Party MP, agreed.

"I think when people begin to understand the full ramifications of it, people will become very concerned," he said.

Some conservatives also fear the issue will cost the party a lot of votes in the next general election. If passed, the bill would come into effect in 2015, right ahead of that election.

The newly elected archbishop of Canterbury Justin Welby reiterated his opposition to gay marriage after his confirmation Monday.