The BBC has quit Stonewall's controversial Diversity Champions programme over concerns about impartiality.

In a statement on Tuesday, the broadcaster said it was also stepping back from the LGBT lobby group's Workplace Equality Index, which scores participating organisations on diversity and inclusion.

The BBC said the decision had been made "after careful consideration".

"Along with many other UK employers, the BBC has participated in Stonewall's Diversity Champions Programme to support our objective to create a fully inclusive workplace. However, over time our participation in the Programme has led some to question whether the BBC can be impartial when reporting on public policy debates where Stonewall is taking an active role," it said. 

"Being a part of the Diversity Champions Programme has never required the BBC to support the campaigns of Stonewall, nor its policy positions.

"As a broadcaster, we have our own values and editorial standards - these are clearly set out and published in our Editorial Guidelines.

"We are also governed by the Royal Charter and the Ofcom Broadcasting Code. Our journalists continue, as ever, to report a full range of perspectives on stories." 

Although the BBC is quitting the Diversity Champions and Workplace Equality Index schemes, it has said it will continue to work with Stonewall and other external organisations "on relevant projects to support our LGBTQ+ staff."

The announcement follows an investigative podcast series by BBC journalist Stephen Nolan questioning the broadcaster's relationship with Stonewall. 

Former BBC investigative journalist Sam Smith told the Nolan Investigates podcast that some people at the corporation were afraid to say what they really think about Stonewall. 

"How can it not have a chilling effect when it is writ large across the BBC that we are a [Stonewall] champion. I can't think of anything else that the BBC has done that's in the same ball park," said Smith. 

She added, "The trouble is the impartiality element of this, for people who do not agree with Stonewall's campaigning position on the gender identity issue, it is not nice for an organisation to align itself with Stonewall and Stonewall's mission."

Discussing his series with The Times, Nolan said he had been warned against reporting on Stonewall by BBC colleagues.

The series' co-creator, journalist David Thompson, said, "What these organisations are essentially doing is paying a lobby group to lobby them. Taxpayers' money is being spent on this."