Numerology

£400m. It's one of the few figures worth chasing down in the 28-page proposal from the BBC Executive, to spin off some of BBC production as a new commercial subsidiary, BBC Studios.

"Based on its current business, BBC Studios will have total revenues of around £400m at launch."

Let's see if we can spend that. The new division/company will have "a fluctuating workforce of around 2,000 people". (Nice scary word, fluctuating.) The average BBC salary last year was £51,500. So a wage bill of £103m p.a.might be a good guess - unless, of course, the caps come off. BBC Worldwide's average salary was £67k, which would move Studios to £134m.

The BBC currently attempts to enforce in-house talent costs at 16% of total spend. Will that apply to S-S-Studios ? £64m ? What target profit margins will be set ? 15% ? ITV Studios returned 17% in its last figures.

The BBC Annual Report shows total support costs for content and distribution at £409m. Taking the Studios workforce at 10 per cent of the headcount, you might expect some of those content costs - property, HR and training, technology - to follow the transferring staff. Let's take a conservative £20m for that. I'd like to add £5m for "restructuring", presuming staff who don't fancy the Salmon leap can take redundancy/re-training/re-settlement. There may be staff Salmon doesn't fancy.

Then there's pensions. Last year the BBC used £188m of licence fees to reduce the pension deficit. 10% of that ought to follow staff into S-S-Studios. And then there's planning to cover the pension liabilities of staff TUPEd at a later stage into a full subsidiary. Studios will have to pay some royalties back to the BBC mothership for being gifted big brands like Dr Who and Strictly. I'm guessing that there'll be some spending on marketing, travelling, entertaining and pitching for new business, and visiting the various UK outposts of the new group. Of course, once a full subsidiary, those elements go off Freedom of Information radar.

A year's worth of EastEnders cost £30m to make in 2010/11. I suspect it's gone up. Who covers the cost of the new set ? Holby and Casualty were reported at a total of £41m in the same report.

We're promised "a flatter structure, with fewer hierarchies and more autonomy for talented individuals; a flexible operating model, supporting best-in-class commercial efficiency; and an entrepreneurial culture, ready to respond to new opportunities wherever they may arise". Lovely - wouldn't the rest of the BBC like that, Lord Hall ?