After a series of outbursts that one senior party colleague called 'increasingly erratic and ill-advised', Lord Ken Maginnis, the former Ulster Unionist Party whip in the House of Lords, has sent a condemnatory email to a Conservative Party think-tank which supports same-sex marriage.

According to the Newsletter, Lord Maginnis, the veteran Ulster Unionist, was reportedly infuriated that the conservative group Policy Exchange had argued in favour of allowing gay couples to marry.

On Saturday, Lord Maginnis sent an email to Policy Exchange's director Neil O’Brien, which he also shared with journalists, senior UUP figures and two leading churchmen.

In the email, Maginnis said that he was not homophobic but was opposed to the Government’s 'perverse' proposal for same-sex marriage. Critics have scoffed at his claims however, since Maginnis was stripped of the UUP whip last month after he made blatantly homophobic comments describing homosexuality as 'a rung on the ladder to bestiality.'

Maginnis told O’Brien in his letter that he would now 'campaign against' Policy Exchange because of its support for same sex marriage.

Among those to receive copies of his email were UUP leader Mike Nesbitt, Church of Ireland Archbishop of Armagh Alan Harper and his predecessor, Lord Eames.

Lord Maginnis wrote: 'I spoke to someone last week – it may have been yourself – to express my disgust that a Tory think–tank would promote 'same-sex' marriage – which I now note they have re-titled 'equal marriage.'

'Being a firm opponent of this perverse proposal – let the Government find its own way to cope with property and financial rights of people engaged in this way of life – I now find it necessary to campaign publicly against Policy Exchange, the wisdom of financing it by private sources and the dubious nature of its 'independence.'

'I am not homophobic but totally oppose the imposition of this practice on the institution of marriage which derives its purpose and meaning from biblical sources. Please remove my name from your emailing directory.'

Policy Exchange last week published a report which said that 'the balance of argument favours equal marriage,' a sentiment Maginnis could not accept.

In their document, Policy Exchange wrote: 'We think legal safeguards should be put in place to prevent religious bodies from having to perform same-sex marriages on their premises but . . . there is no good reason why gay couples shouldn’t have the right to get married. The Evening Standard trailed the report’s findings on Friday and also penned a leader column praising the research and urging the Prime Minister to push through the reforms.'

When contacted by the News Letter for a comment, Policy Exchange replied: 'Thanks for alerting us to Lord Maginnis' email. He’s obviously entitled to his own opinion.'

Ulster Unionist Ken MaginnisPhotograph: Paul Faith/PA