Image caption Danish actor Lars Mikkelsen (centre) starred as blackmailer Charles Magnussen

The final episode of BBC One drama Sherlock, starring Benedict Cumberbatch and Martin Freeman, has been reviewed enthusiastically by TV critics.

The Guardian's Lucy Mangan called His Last Vow "perfect", praising the series finale for its "ceaseless flow of wit, invention and intelligence".

Calling it the "best of the lot", the Daily Telegraph's Serena Davies singled out writer and producer Steven Moffat.

Sunday's final episode drew an average audience of about 8.8 million.

That was less than the average of 9.2 million people who tuned in on New Year's Day to see Sherlock's opening episode, the first instalment since in 2012.

Image caption The episode featured several twists, one involving John Watson's new wife Mary

The second episode, which saw Martin Freeman's John Watson wed his fiancee Mary, saw a slight drop, with an average audience of 8.84 million.

The Telegraph's Davies praised Moffat for getting "the wary dance between plot and character just right".

Her review also saluted Danish actor Lars Mikkelsen for his performance as media mogul and master blackmailer Charles Augustus Magnussen.

"As Magnussen, he licked one of his appalled victims. And in one sequence, excellent in its understatement, he repeatedly flicked Watson in the eye as if his finger were the tongue of a snake," she wrote.

'Bromantic lull'

"If he'd chopped him up with a saw it couldn't have been more horrid."

Metro also paid tribute to the former star of The Killing, suggesting the storyline of a manipulative media boss tapped into public fears about phone-tapping and intrusion.

"From his position as a media mogul, he acquires compromising evidence on people, which gives him the power and wealth to gain even more information and therefore influence.

"That's a notion which strikes a chord with modern-day concerns about surveillance and personal data."

"After the bromantic lull of last week's wedding episode, in which the mystery plot was half-drowned in sentiment, there was reason to fear Sherlock had gone soft," said The Independent's Ellen E Jones.

Image caption His Last Vow, which also featured Lindsay Duncan (r), drew an audience of 8.8 million

"We should have had more faith."

In a different review on the newspaper's website, however, Neela Debnath called it "a disappointingly desperate finale".

"Sherlock is known for being clever, but this time it is trying far too hard and is coming across a tad foolish," she wrote.

The latest episode was something of a family affair for the production team, featuring Freeman's partner Amanda Abbington as Mary and Cumberbatch's real parents as the parents of Sherlock and Mycroft Holmes.

It also featured Moffat's son Louis in the flashback role of Holmes during childhood.

In his review, the Daily Mirror's Josh Wilding said the programme had featured "some amazing visual sequences, a number of clever twists, a truly detestable villain and a strong story".

Thanks to these, he continued, Sherlock "continues to show why it is simply one of the greatest TV shows of all time."