As BSkyB prepares to report its latest batch of results on Friday, Jeremy Darroch, chief executive, can afford a wry grin. Unlike its competitors, Sky has had a good recession. With just 6 per cent of its revenues derived from advertising, the satellite TV group, 39 per cent owned by Rupert Murdoch’s News Corp, has been insulated from the decline in ad spending that hit free-to-air broadcasters this year. Setanta, Sky’s biggest pay-TV competitor, folded in June. And while terrestrial rivals ITV, the BBC and Channel 4 have had their efforts to collaborate on internet-based services held up by regulators and the BBC Trust, Sky has forged ahead with its own online plans: last week it launched Sky Songs, a music service designed to compete with Apple’s popular iTunes store.

Investors will be keeping a close eye on how Sky manages the cost of its growing empire. Sky looks on track to hit its target of 10m subscribers next year, up from 9.4m in June. But growth has come at a price: JPMorgan reckons higher marketing costs and investment in add-on services such as broadband and high definition TV saw margins fall to 14.7 per cent in the year to June, from 16.8 per cent two years earlier. A key question for Friday is whether that slide has started to reverse as those investments pay off, and existing customers upgrade their basic pay-TV service. Such up-selling will only become more important if Ofcom, the UK communications regulator, succeeds in its bid to force Sky to share some of its premium sports and film content with rivals.