Conservative blogger Tim Montgomerie believes a failure to accommodate the views of “traditionalists” who oppose equal marriage has contributed to the rise of the UK Independence Party.
Mr Montgomerie, who founded ConservativeHome, wrote on the website that “Illiberal liberals” were among “the ten creators of UKIP”.
He said: “I support gay marriage (shamefully, I was resistant to homosexual equality but now have the zeal of a convert) but, but, but I don’t think most traditionalists are homophobes.”
The journalist and political commentator also suggested it was wrong to call UKIP supporters bigots or “racist”.
He said marriage should be “for gay people as well as for straight people.”
Another poll, commissioned by the anti-gay Coalition for Marriage days before last week’s local and European elections, found that 23% of Tory supporters felt same-sex marriage was a reason not to vote for the party.
UKIP remains opposed to equal marriage.