Sherlock beats the Queen in festive TV ratings
More than eight million people tuned in to see the return of Sherlock on BBC One on Sunday, overnight ratings show.
That means it was the UK's second-most watched programme of the festive period - behind the New Year's Eve fireworks, which were watched by 11.6 million.
The biggest Christmas Day audience came for the Queen's Christmas message, which was seen by 7.7 million people.
The first episode of the fourth series of Sherlock had an average audience of 8.1 million.
The episode, entitled The Six Thatchers, was based on Arthur Conan Doyle's story The Adventure of the Six Napoleons and involved six smashed statues of the former UK prime minister.
It "reached new heights of action and emotion", according to The Guardian's Mark Lawson, who saw parallels between Benedict Cumberbatch's Sherlock Holmes and James Bond.
He wrote: "The episode felt very Bond overall - Holmes has never done so much running towards or away from explosions."
'A dizzying triumph'
The Telegraph's Ben Lawrence wrote that it was "a dizzying triumph of complex plotting (although the much-talked-about demolition of six busts of Margaret Thatcher was an unnecessary piece of iconoclasticism) and beautifully choreographed action scenes".
Martin Freeman has made Watson "a nuanced, compelling character", he said, but added: "It is, of course, Cumberbatch's show and here he looked tanned and lean, ready for action but heading, ultimately, for a fall.
"Cumberbatch is an actor who invests so much in every scene that watching him is an exhilarating experience and an almost psychological exercise."
The programme's overnight ratings were slightly down compared with those for last year's New Year's Day one-off Sherlock special, which had 8.4 million.
Elsewhere in Sunday's BBC One schedule, Mrs Brown's Boys was watched by an estimated 6.7 million, while six million saw Ronnie and Roxy Mitchell's demise in EastEnders.
EastEnders narrowly lost the battle of the soaps to Coronation Street, which attracted 6.2 million on ITV.