Pressure has been cranked up on the BBC to invest a fairer proportion of licence fee cash in the Midlands after the Prime Minister said the region must get a "fair bang for its buck".

The Post launched a campaign for fairer investment after it emerged the broadcaster invests far less in the Midlands than any other region – £12.40 per head compared to £755 per head in London.

With the debate over a new ten-year BBC charter expected to begin in May, Prime Minister David Cameron said the issue of unfair spending levels in the Midlands should be on the table.

Leader of the Opposition Ed Miliband has also called for the BBC to look into the shortfall in investment.

The Midlands contributes £942 million a year to the BBC through licence fees but only about £80 million was re-invested here last year. The Post has demanded half of all money raised here should be reinvested in the region.

Speaking to the Post, the Prime Minister said: "It doesn't sound fair and these are the questions we will be able to ask in the charter renewal process which starts after the election.

"I am a fan of the BBC. I think it does produce quality news and quality programmes.

"Part of the advantage of the BBC should be, with all the money that comes into it through the licence fee, that they can really do long-term investment into regional news and current affairs and we need to make sure that happens.

"And it is not just news and current affairs. We want dramas and documentaries that reflect the different regions and cultures of our country and the BBC should be doing that.

"Yes, the charter renewal is a good time to have that conversation and make sure the West Midlands gets a fair bang for its buck."

Pressure has increased on the BBC's management to increase investment since the campaign was launched last month.

A petition has been started calling for the Culture Secretary to act while city MPs Gisela Stuart and Steve McCabe have taken the fight to Parliament.

Production industry figures say investment levels – which are a fraction of that spent in the North and London – have squeezed the life out of a once proud local sector.

There are no network television production studios in the region and no prime-time television production takes place here.

The BBC Trust has set a target of seeing 50 per cent of network budget spent outside London by 2016. Despite that, while investment in all other UK regions has risen – Wales, Northern Ireland, Scotland, the North and the South – it has fallen here in the past five years.

Labour leader Ed Miliband said the BBC should address the problem.

He said: "I think the BBC should be looking at this. I understand it is lower in the West Midlands than in any other region."

Mr Miliband praised the BBC for devolving some spending, moving staff and operations out of London and in to Salford, Greater Manchester.

However, he added: "What the BBC has done in relation to Salford is really good – but I think then the Midlands will be saying they want a piece of the action, and I totally understand that.

"It is a matter for the BBC, not for me, but I'm sure they'll want to look at it."

BBC director general Tony Hall pledged to boost the BBC's investment in Birmingham after taking on the roll in 2013.

Birmingham-born Tommy Nagra was parachuted in as head of BBC business development in the city in 2014.

As a result 81 jobs are set to be created by bringing the HR department and the BBC Academy to the Mailbox and about 190 will be created at the Birmingham headquarters in all.

However, investment levels are expected to remain significantly lower than any other BBC region.

The BBC declined to comment.