Nearly 10 million viewers tuned in to find out how Sherlock survived his rooftop plunge on BBC1 on Wednesday night, the acclaimed drama's biggest audience yet.

The third series of the Benedict Cumberbatch and Martin Freeman drama began with an average of 9.2 million viewers between 9pm and 10.30pm, peaking with 9.7 million for its first five minutes.

Sherlock had the highest audience of the day but not the biggest of the holiday period, unable to top an opponent even more powerful than Moriarty – Mrs Brown's Boys, the BBC1 sitcom which drew 9.4 million viewers on Christmas Day.

It was more than the 7.5 million viewers who saw the opening episode of the first series in July 2010 and the 8.8 million who watched the start of the second series on New Year's Day 2012.

The mystery of how Sherlock survived remained just that – a mystery – after the show's opening explanation featuring Derren Brown proved a red herring.

Sherlock went on to say there were 13 ways in which he could have avoided his apparent certain death, but viewers hoping for a definitive answer would have been left disappointed.

Sherlock pulled in a 33.8% share of the audience.

The BBC1 drama was up against the terrestrial premiere of the concluding part of Harry Potter and the Deathly Hallows: Part 2 on ITV.

The movie was watched by an average of 5.1 million viewers, a 19.2% share, between 8pm and 10.30pm.

As well as Sherlock, the bespectacled wizard found himself up against an hour-long edition of EastEnders on BBC1, watched by 7.3 million viewers (27.8%) between 8pm and 9pm.

Steven Moffat, who co-created the show with Mark Gatiss, said: "Thrilling news on overnight ratings for Sherlock.

"A tribute to the team who work so hard, and with such pride, on the show, and of course to the genius of Sir Arthur Conan Doyle.

"It's proof that audiences will show up if you give them what they want - though we can't throw Benedict off a roof every week."

Gatiss, who wrote last night's episode, added: "Delighted our loyal audience tuned in on an appropriately bleak and stormy New Year's night!

"After two years it's fantastic to have this response to Sherlock, John and all the team being back on TV. All this and Dr Watson gets married in three days time!"

Under a blood red sky, a crowd has gathered in black and white ... (to watch a 42 inch flatscreen in HD)

Elsewhere on New Year's Day, David Attenborough's Natural History Museum Alive, in which Attenborough spent some screen time with dinosaurs and a dodo, began its 3D voyage with an average of 583,000 viewers, a 2.4% share, between 6.30pm and 8pm on Sky1.

BBC1 terrestrial film premiere Gnomeo and Juliet had 4.2 million viewers, a 16.6% share, between 6.45pm and 8pm.

It lost out to ITV's double soap helping of Emmerdale, with 6.7 million (27.2%) between 7pm and 7.30pm, and Coronation Street, watched by 8.3 million viewers (32.2%) between 7.30pm and 8pm.

David Blaine delivered Channel 4's biggest audience of the day, his return to street magic, David Blaine: Real or Magic?, watched by 2.5 million viewers, a 9.2% share, between 9pm and 10pm.

It was marginally less viewers than BBC2's own weird events, Nature's Weirdest Events, which had 2.6 million viewers (9.9%) between 8pm and 9pm, BBC2's top rating show.

A case of new year, old schedule on Channel 5, with An Audience with Ken Dodd repeat (from 1994) scoring the channel's biggest audience, 1.3 million, a 5.1% share. It was ahead of another showing for 1954 war film The Dam Busters, which had 1.1 million viewers (4.3%) between 6.30pm and 8.55pm.

All ratings are Barb overnight figures, including live, +1 (except for BBC channels) and same day timeshifted (recorded) viewing, but excluding on demand, or other – unless otherwise stated. Figures for BBC1, BBC2, ITV, Channel 4 and Channel 5 generally include ratings for their HD simulcast services, unless otherwise stated

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