A flood has descended upon Baker Street as the Sherlock (Benedict Cumberbatch) and Watson (Martin Freeman) face off in the latest teaser for Sherlock series 4.
Kicking off on New Year’s Day, Sherlock’s three-episode run begins with The Sixth Thatchers – which seems to be a play on Arthur Conan-Doyle’s Holmes tale The Adventure of the Six Napoleons.

Written by Mark Gatiss, the BBC have also revealed a few more clues about the upcoming episode.
A statement said:
“Sherlock waits to see where Moriarty will make his posthumous move. One mysterious case in particular baffles Scotland Yard – but Sherlock is more interested in a seemingly trivial detail. Why is someone destroying images of the late Prime Minister Margaret Thatcher? Is there a madman on the loose? Or is there a much darker purpose at work? Something with its roots deep in Mary Watson’s past…”
Quite how this all ties into the flood of Baker Street – and one very large home insurance claim – and Sherlock’s final proclamation at the end of The Abominable Bride that he ‘Moriarty is dead. More importantly, I know exactly what he’s going to do next…’ remains to be seen but if there are clues to be found, no doubt there are many contained within this image too.

Sherlock series four: The Six Thatchers is on New Year’s Day, 1st January 2017, at 9pm on BBC1