Last night ITV ran TV's Biggest Blockbusters, looking at the most watched shows on British television in several categories. It was an interesting programme, particularly when it highlighted shows that are now completely forgotten (e.g. Oh No it's Selwyn Froggitt, Market in Honey Lane or Mrs Thursday) or showing which comedians were more popular - it's a shock to discover that Mike Yarwood got slightly more viewers than Morecambe and Wise at their height when you consider the coverage each has got since.
However they repeated at least one big error in compiling their list - the claim that on Christmas Day 1986 30.15 million watched EastEnders (and thus Den giving Angie divorce papers was the most watched drama of all time). This is repeating a common misunderstanding of how the viewing figures worked, and reflects the BBC boasting at the time.
The given figure actually combines the viewers on Christmas Day itself with those for the omnibus repeat the following Sunday. About 19.5 million actually watched on Christmas Day - still a very impressive figure but not as good for boasting and often the media (and TV's Biggest Blockbusters researchers) overlooked the distinction. This was despite the point being made at the time - Granada complained more than once when Coronation Street, which then didn't have a repeat, get more viewers than the first screening of EastEnders but the latter got written up as the "winner" of the ratings battle. It's a pity that these myths get trotted out all these years later.
What was the most watched drama of the 1980s? It was in fact a movie - the January 20th 1980 screening of Live and Let Die with 23.50 million viewers.
So how many of the other figures and chart places can be taken as accurate? It's hard to say because there are several problems with viewing figures, not least the lack of a single industry wide system before 1981 and ITV counting households rather than heads until 1977. There's a further problem that the recording systems haven't always been very good at catching crowd viewers in pubs, schools, workplaces, open air screens and the like and so the precise figures for some shows may be undercounted. This most obviously hits live events like sport and Royal Weddings, but further down the charts could also hit current affairs shows and documentaries that might attract group watching with special parties at people's homes or discussion groups. Discussing Question Time live with other viewers didn't begin with Twitter!
One of the best written intros to how figures have been calculated historically that I've seen is Corriepedia: Viewing Figures (and no, I've never been a Coronation Street fan). It also highlights that back in the 1960s and 1970s Christmas Day was often one of the worst days for soap viewing figures, and there was a period in the 1970s when Coronation Street would actually skip Christmas Day altogether! How times have changed.
And other than live events we'll probably never see such high viewing figures again. Not only are there far more channels now, but with many shows having multiple screenings in a week plus the growth of one hour later channels and programmes on demand, audiences are becoming ever more fagmented. Timeshifting through digital and video recorders is generally incorporated into the final viewing figures for a show but with so many other opportunities to watch a programme there isn't a huge audience all at once.
But there are still exceptions when an event is live. Invariably they're Royal events.