UPDATE: The debate on the bill is taking place on Feb. 5. Streaming live.
Conservative Party members in Britain have written to their leader, Prime Minister David Cameron, to urge him to delay a parliamentary vote on gay marriage.
The politicians warned that the ruling party will lose significant numbers of voters in the 2015 election if the plans enter law.
However, lawmakers are debating the bill on Feb. 5, with a vote expected later in the day.
The measure would enable same-sex couples to get married in both civil and religious ceremonies. It would also allow couples who had entered into civil partnerships to convert their relationship to a marriage.
More than 20 heads of local Conservative associations delivered to Downing Street a letter urging a delay in the vote.
Cameron supports the bill, but the issue has divided his Conservative Party.