[DTV]

Separately, people keep mentioning how advertisers will be fleeing if World's programming choices chase away too many viewers but do we know exactly how much is made through advertising and how much simply through pay-TV packages? When I was in HK, there were never any (or very rarely) any ads on BBC World but it was part of a pay-TV package so I suppose it's at a rate which the BBC negotiates with each pay-TV provider individually?

According to the latest year that figures are available, BBC Global News' television advertising income was £27.8m, compared to £15.8m from licence fees and £6.3m from syndication fees, plus an extra £41.8m from other sources - primarily digital advertising income.

I don't think it's really a case of advertisers fleeing, but any decline in audience figures would reduce the rates that the BBC can leverage out of advertisers. Similarly, with pay-TV contracts, the BBC's hand in negotiations will be somewhat dependent on what audience they are legitimately able to claim. The same applies to the few sponsored programmes the channel has.

In terms of ads, there is variation between markets - both in terms of frequency of adverts and the rates that are charged (the US market is the big one). But really, it's all about the sheer bulk of adverts that's where the money comes from. I don't have a BBC World ratecard to hand, but BBC Earth Asia's ratecard on the BBC Studios' website suggests $250 for non-peak, $500 for peak for a 30-second ad. Just two minutes of ads an hour, every day would add up to $11.7m (currently £9.5m - ads are sold in $, so USD:GBP exchange rates do affect profitability) per year in just one market (of course, they don't necessarily sell this many in each market).