Stacey is Archie Mitchell's killer!

Stacey Branning has been revealed as Archie Mitchell's killer in a special live episode of EastEnders to mark the soap's 25th anniversary.

The episode brought to an end one of the biggest mysteries in the soap's history, following Archie's murder by an unseen assailant in the Queen Vic on Christmas Day.

It featured many of the possible suspects - including Peggy Mitchell, Ronnie and Roxy Mitchell, Phil Mitchell, Ian Beale and Janine Butcher - pointing the finger of suspicion at one another, as Bianca and Ricky's wedding celebrations continued at the Vic.

The ensuing action saw Phil ransacking Ian's house looking for evidence, a dramatic confrontation between Janine and Peggy and Ronnie confessing to Roxy that Archie had sexually abused her, after she accused her of the murder.

However events came to a tragic end when the police, who suspected Bradley of the crime, came to arrest him as he attempted to flee Albert Square with his new bride Stacey.

The dramatic chase ended with Bradley falling from a rooftop to his death while trying to escape the police - with the final shot a hysterical Stacey confessing to Max that she was the killer.

Stacey had confessed to Bradley on Christmas Day that she had been raped by Archie and claimed she was pregnant with his baby - giving both of them a motive for the crime.

However Lacey Turner, who plays Stacey, almost missed out on her chance to take part in the episode after she was diagnosed with flu and lost her voice. According to reports, the 21-year-old rehearsed silently throughout the day in order to be fit for Friday's episode.

The live episode featured 51 members of the cast, who had been rehearsing for three days, and went smoothly apart from actor Scott Maslen, who plays Jack Branning, briefly fluffing his lines at the start of the show.

The identity of the culprit had been kept so closely under wraps that 10 possible endings had been written, while Turner was only told that Stacey was the killer half an hour before the epsiode went on air.

Speculation had been mounting over the guilty party since the Christmas Day edition aired, with Sean Slater - Stacey's brother, who hasn't been seen in the show since January 2009 - emerging as the last-minute favourite with the bookies.

Second favourite, according to William Hill, had been Phil Mitchell's young son Ben, played by actor Charlie Jones, followed by Stacey's friend Becca Swanson (Simone James) and Danielle's father Joel Reynolds (Cavan Clerkin)

A last-minute flurry of bets had also put Queen Vic barmaid Tracey, played by actress Jane Slaughter, in the running.

The bookies said that they anticipated £1m to have been staked on the outcome by the time the market closed, just seconds before the identity of the killer was revealed. The total was expected to break the record £100,000 set by the Who Shot JR? storyline in Dallas in the 80s.