The Law Society has called off a conference that was set to debate gay marriage at its headquarters this month due to a conflict with the society's "role in promoting diversity."

The event, set up by US organisation World Congress of Families in partnership with UK lobbying group Christian Concern, was set to be held at the Law Society's London base next Wednesday (23 May).

However, the society has cancelled the event in light of the topics up for discussion.

Family division High Court judge Paul Coleridge had been lined up as one of the main speaker's at the event, which was set to debate "the issues surrounding the Government's proposed redefinition of marriage", including its plans to allow same-sex marriages.

The event's publicity materials state: "The Government itself speaks of the value of marriage but simultaneously seeks to redefine it and undermine it." Other speakers due to talk at the conference included family barrister Peter Duckworth of 29 Bedford Row and Telegraph journalist Cristina Odone.

Law Society chief executive Desmond Hudson said: "We are proud of our role in promoting diversity in the solicitors' profession and felt that the content of this conference sat uncomfortably with our stance. Through our events and venues supplier, we have offered to assist the organisers in identifying an alternative, non Law Society venue."  

The event, titled "One man. One woman. Making the case for marriage, for the good of society", was set to follow the launch of Coleridge's new charity, the Marriage Foundation, earlier this month. The charity aims to be a "national champion for marriage" with the promotion of relationship support and education.

In a statement, Andrea Williams, CEO of Christian Concern, said: "We're not looking at another venue. I've not spoken to them about another venue. We're asking the Law Society to honour its contract with us. I was called to the Bar in 1988 and am proud of our country's long and great legal history. I will not be hounded out of a legal institution for holding a debate on marriage."

"This colloquium was intended to be a genuine open debate on the issues, constructing a case for marriage in the public sphere, and they seem to be closing it down. Of all the places in society where you might expect freedom of debate to be protected, the regulatory body of the legal profession would surely be at the top of the list."

The news comes as the Government is in the midst of a consultation to legalise gay marriage with an aim to change UK law on the subject by 2015.