A controversial gay cleric will be one of the attractions a Christian music and arts festival being held in Cheltenham this Bank Holiday weekend.

The Greenebelt Festival was first held in 1974 and this year around 20,000 people are expected to attend over the four days.

It is an eclectic event. Bands such as Royksopp and Sixpence None The Richer are headlining.

Government ministers David Lammy and Douglas Alexander will be appearing at Greenbelt and there will also be a talk by Gene Robinson, Anglican Bishop of New Hampshire, who is openly gay.

His inclusion in the festival was criticised by conservative pressure group Anglican Mainstream.

“Gene Robinson was invited because he’s a controversial celebrity. So I suggest it’s a sign of prejudice by Greenbelt that they haven’t invited other speakers,” a spokesman said.

Divisions over gays in the Anglican church erupted in 2003 when Gene Robinson was consecrated as a bishop.

His appointment caused deep rifts between liberals and traditionalists.

In the last three years, the Anglican Communion has been pushing the US Episcopal Church to “restrain” the numbers of gay bishops in order to avoid a split in the Anglican church. No new gay bishops have been consecrated in this time.

There is also a Christian LGBT event on Sunday at the Greenbelt Festival.

“OuterSpace is a group of LGBT (lesbian, gay, bisexual, transgendered) Christians, and their family and friends, at the annual Greenbelt Festival. It is committed to the Church and to helping everyone find their way in the Church, no matter what their background,” according to the festival website.

“OuterSpace tries to look beyond the dry intellectual debates that surround the whole area of sexual orientation, and to focus instead on the stories of real people’s faith, in order to understand the different journeys that gay and lesbian Christians are on.

“It is only by enabling people to share their experiences and to engage in constructive dialogue, that the Church can begin to reflect the reality of the world around it.

“Through humanising the debates, the Church will more effectively make a positive difference to the lives of believers and non-believers alike.”