Channel 4 has enjoyed a remarkable 18 months of critical and ratings success, in the process maintaining its overall audience share at around 10%. No mean feat when the other four analogue networks' audience shares have been tumbling. But could this run be about to end?
The broadcaster's successes since the start of 2005 have been well documented, but have included Jamie's School Dinners, Desperate Housewives and Lost. Extended runs of Big Brother - both the original and celebrity versions - have also helped boost Channel 4's audience share.
But the biggest driver of Channel 4's ratings success story over the past 12 months has not been peaktime shows, but its afternoon line-up of Countdown, Deal or No Deal and The New Paul O'Grady Show.
And out of that trio, it is Noel Edmonds' runaway hit game show, Deal or No Deal, that has been single biggest factor in boosting Channel 4's ratings performance.
Deal or No Deal regularly attracts a share of more than 30% in 4.15pm-5pm slot, where previously Channel 4 was averaging around 20%.
So for five days a week since Deal or No Deal launched on October 31 last year, Channel 4 has enjoyed a massive boost to its year on year share during that time period.
Channel 4 head of daytime Adam Macdonald estimated at the MediaGuardian Edinburgh International Television Festival last month that Deal or No Deal was the difference between the broadcaster's share for the year up to that point being 10.4%, instead of 9.7%.
But after October 30 this year, when year on year comparisons for Deal or No Deal will be with old editions of the same show, Channel 4 will no longer benefit from that automatic boost to its ratings.
And with ITV in talks with Ofcom about ditching its children's programming from ITV1's weekday afternoons, it seems likely that from some point next year Channel 4 will face far more competition between 3pm and 4pm, when Countdown is on air.
It's hard to see where else Channel 4 will get year on year ratings growth from. Former peaktime ratings winners such as Wife Swap, Supernanny, Desperate Housewives and Lost are not attracting the figures they used to and Channel 4 director of programmes Kevin Lygo has indicated that the broadcaster is likely to cut back on Big Brother next summer.
New Channel 4 output for the autumn includes the Footballers' Wives-esque sounding drama Goldplated, set in the rich set in Cheshire. But although the network's drama output attracts plenty of critical plaudits, it's been a while since a homegrown series in the genre was a big ratings hit, aside from Shameless.
And what of a new Wife Swap or Supernanny? Well Channel 4's best hope this autumn would seem to be The Secret Benefactor, from Wife Swap producer RDF. Each week a wealthy and powerful "secret benefactor" goes undercover in a deprived area and decides who is most deserving of their time, expertise and cash.
Or maybe there's something out there that will surprise us all, like Deal or No Deal. After all, late last year Channel 4 unleashed, er... Space Cadets on an unsuspecting world.
