A total of 330 MPs have confirmed they will vote in favor of same-sex marriage legislation when it is introduced at Westminster later this year.

In contrast, just 126 Members of Parliament (MPs) have publicly stated that they remain opposed to a change in the law, meaning there is now a clear parliamentary majority for equal marriage.

The figures were released today (16 January) and were a result of a survey conducted by the Coalition for Equal Marriage, a UK campaign organization, is based on public declarations of support or opposition from MPs, including letters to constituents.

It means that the pro-marriage equality lobby not only has a big lead of the politicians who have so-far stated their position but also a slim majority of the total number of 650 members of the UK parliament. So even if all the remainder of the MPs end up opposing gay marriage, the measure should still pass.

Key figures from across the political spectrum have said they will personally be voting for the proposals, including the leaders of the three main parties.

Yvette Cooper, Labour MP and Shadow Minister for Women and Equalities, said: ‘The Labour Party strongly supports same sex marriage. When couples love each other and want to make a commitment, it should be a cause for celebration, not discrimination.

‘Those couples should be able to marry, regardless of their gender or sexuality.

‘Labour votes will ensure that this measure is passed in the House of Commons and we hope the government brings forward legislation as soon as possible.’

Nick Herbert, Conservative MP and founder of the ‘Freedom To Marry’ campaign, said: ‘With the polls showing that a clear majority of the public support equal marriage and now evidence that a majority of MPs will back it, too, this is a reform whose time has come. 

‘Its opponents should recognise the democratic will and focus on ensuring legitimate protections for religious freedom rather than trying to frustrate a change that is so widely supported.’

Stephen Gilbert, a gay Liberal Democrat MP said: ‘Liberal Democrats have long fought for equal marriage and now we’re in government we’re committed to making it happen.

‘That a majority of MPs have come out in favour of is a very significant step forward.

‘The right to love and commit to who you chose is a fundamental one and whether you’re straight or gay, the civil institution recognising that love and commitment should be the same’.

The news comes as polling shows increasing support for same-sex marriage amongst the public.

A recent poll carried out by ICM for the Guardian in December showed 62% of people in favour, with just 31% opposed.

The UK Government is expected to launch same-sex marriage legislation for England and Wales by summer 2013.

Separate legislation for Scotland has already been launched in December 2012 by the Scottish Government, and already has the support of over two-thirds of members of the Scottish Parliament.