The voluntary sector is less keen than the private sector to promote gay, lesbian and bisexual equality in the workplace, according to Stonewall.
Charities make up only 5 per cent of Stonewall's diversity champions programme, which helps organisations recruit and retain gay, lesbian and bisexual staff. Only 12 out of the 240 organisations that have joined the scheme since it started in 2001 are charities.
"They're in the minority," said Alan Wardle, director of public affairs at Stonewall. "The organisations that are keen are all from the private sector."
The British Red Cross is the latest charity to join. Other voluntary sector members include NCH, Mencap and St Mungo's.