One in six of all on-screen BBC roles must go to lesbian, gay, bisexual and transgender or disabled people by 2020, the corporation's new diversity targets state.In a bid to deter criticism that it has been failing to reflect its audience, the BBC has pledged that LGBT and disabled people will each make up eight per cent of all on-air and on-screen roles.The new targets follow a heated debate in the House of Commons led by David Lammy MP on the issue of the broadcaster's diversity.Fifty per cent of all on-screen and broadcasting roles will go to women, who already make up 48.5 per cent of the BBC's total workforce.However, the BBC will still be able to commission shows where the main roles are more likely to be male-dominated.Radio 2, which has a particularly male-dominated line-up of broadcasters, including DJs and presenters Chris Evans, Simon Mayo, Jeremy Vine and Bob Harris, faces an overhaul.Radio 2 was highlighted as having particular difficulties in attracting non-white listeners.The BBC's target for 15 per cent of on-screen and on-air representation, including lead roles, to be people from BAME backgrounds will not be increased by 2020, as the current percentage reflects the UK's population.Currently 13.1 per cent of the BBC's workforce is from a BAME background, with the same target of 15 per cent by 2020.A statement from a BBC spokesperson said: 'We are making good progress in our work to make the BBC a truly diverse organisation, but there's more to do and we're always keen to improve.'Almost half of our workforce is made up of women and the proportion of our workforce who are black, Asian and other ethnic minorities is at an all-time high.'But there is more to do and we know the challenge we face so we'll be building on this strong platform by continuing doing what works.'We'll continue doing what works but also develop new and innovative ideas to do even better, and we'll set this out in our new diversity strategy shortly.'In a statement on the BBC's website, Tunde Ogungbesan, head of diversity, inclusion and succession at the BBC, said: 'The BBC is a diverse organisation, whichever way you look at it.'Later this month we'll be launching our new diversity strategy full of new and innovative ideas for our audiences, for our people and with our partner to do even better between now and 2020.'The BBC said that by 2020 it hopes to 'meet or better' other major broadcasters when it comes to representing the national population.Minister for Culture and the Digital Economy Ed Vaizey confirmed that diversity will be prominent in the White Paper on the BBC's new charter, which will be unveiled by Culture Secretary John Whittingdale in May.The BBC's royal charter, due to expire this year, is currently under Government review.