The true cost of moving BBC operations away from the Mailbox could amount to more than 43,000 licence fees, the Birmingham Post can reveal.

Huge redundancy costs of a month’s salary for every year of service mean that some of those losing jobs could get more than £100,000.

The BBC has suggested that the cost of the move will be £4.5 million, or 30,777 licence fees, in response to a Freedom of Information request.

But according to some estimates from corporation insiders the final bill could come to at least £6.3 million – or 43,000 licence fees.

The move has sparked fury from politicians, business leaders and workers in the city who have described it as “needless”.

Almost 150 people are at risk of redundancy at the corporation’s Birmingham base after the decision to merge factual work with Bristol.

Programmes such as the Hairy Bikers and Countryfile and coverage of RHS flower shows will move from BBC Birmingham’s base at The Mailbox from August.

A corporation insider told the Post a more realistic estimate of the cost is nearly £2 million more expensive, at around £6.3 million or 43,000 licence fees.

The BBC figures show that 100 people are at risk of redundancy in television – 58 staff have been offered places in Bristol – so at least 42 will be made redundant.

The corporation said average redundancy costs in “Vision” would be around £38,000 per person and home owners would be offered £23,000 to relocate and “significantly less” for people renting.

In radio, 36 people are at risk of redundancy – 22 have been offered the chance to relocate – therefore at least 14 people will lose their jobs.

Average redundancies per head in “Audio and Music” will be around £58,000, with relocation payouts of £23,000.

The BBC assumes the cost of dual running – running teams in Birmingham and Bristol – for two months to be £230,000.

The BBC insider told the Post the projected costs were “ludicrously low.”

The source said: “Given the length of service of many of the staff in Birmingham, and the fact that it’s the long serving people who are most likely to take redundancy, the figure of £38,000 per person for an average estimate in Vision is hopelessly low.

“There are maybe 10 people who are in line for £80,000 to £100,000. BBC redundancy pay is a month for every year.

“They have also given the relocation figure as £23,000 which is wrong because if people take their whole allowance it will be £31,000 each.

“Of course, none of these numbers include the costs of upgrading White Ladies Road in Bristol to accommodate the new staff, nor the costs of either mothballing the Mailbox, paying off the rent early or moving other staff in.

“The cost given of ‘double running’ is optimistic.

“The other key expenditure missing from these calculations is the additional staff who have been drafted in to help the move – there is now a ‘move executive’ employed – and every week key staff and external people, estate agents, educational experts etc, are coming to Birmingham.

“Their fees and their travel costs don’t feature in this calculation.”

The source said staff were given three months to make a decision, with a deadline in mid-February.

The BBC source added: “Without a strong BBC presence in the city Birmingham will become just another provincial city, while Manchester, Cardiff, Glasgow and now Bristol forge strong international reputations as centres of excellence for factual.

“This will have a massive knock on effect to independent production companies and freelance staff. I dispute that this will come into cost savings – they will not be able to save this money.

“Licence fee payers from the Midlands account for 15 per cent of the total, but the Midlands gets back about three per cent and that is before the cuts.

“The assertions that Birmingham is one of the smaller factual departments is just wrong and needs to be dealt with separately.”

Rachael Ward, from the BBC’s Information Policy and Compliance, in responding to the FOI, said: “In Vision Factual Productions we are simply spread too thinly, with four English bases – London, Bristol, Birmingham, Salford – as well as bases in Cardiff, Belfast and Glasgow.

“Birmingham is one of the smallest bases, and most susceptible to job losses through single commissioning decisions and too small to justify the significant investment in new technologies that will drive efficiencies elsewhere.

“As a result we have decided to merge our factual teams in Birmingham and Bristol. By consolidating our features output into Bristol we can also build on our creative collaboration with colleagues in Wales.

“This decision to merge Bristol and Birmingham is driven by a strategic decision to have fewer, more sustainable factual bases across the UK as the best means to continue to deliver quality programming. As such it isn’t driven solely by a budgetary savings target.”

Ms Ward added: “It should also be noted that although this change is a creative decision, there will be financial benefits.

“For example by consolidating into Bristol we will avoid duplicating technology investment spend, reduce senior management headcount and improve overall staff utilisation levels.

“Audio and Music has also reviewed the work across its England bases and decided to reduce the number of sites on which it maintains a full network production capacity and so consolidate its English bases by moving most of the Radio Production teams currently based in Birmingham to Bristol and Salford.

“Estimated dual running costs of £230,000 is a high level estimate and will need to flex depending on the interest in relocation versus redundancy.

“The Birmingham base will also be impacted by the wider Delivering Quality First proposals and the efficiency savings being made across the board, so the above only represents the impact of the moves themselves.”

The controversial move to Bristol has sparked protests in Birmingham, and a walkout from staff took place last month.

Midland MPs have criticised the decision, describing it as a betrayal of the Second City. Birmingham MP Steve McCabe (Lab Selly Oak) told the house of Commons: “Is it fair that viewers in the West Midlands should have to pay the same licence fee as viewers in Cardiff, Bristol or Salford when the former get such a limited return for their investment compared with the latter?”

Valerie Vaz (Lab Walsall South) added: “What concerns me most as a West Midlands MP is the proposed decimation of BBC West Midlands, which has a unique 90-year history of both factual and drama programme making.”