On Sunday night, Sherlock fans tuned in to the finale episode of the BBC series' fourth season; "The Final Problem". Unfortunately for the British broadcasting institution, an unanticipated problem of their own occurred, when the episode was illegally leaked online a day before the official air date.

Although the source of the leak is at this time unknown, a channel continuity announcement, plus language dubbing present within the leaked version, suggests it originated from Russia's Channel One. This, in turn, creates suspicion that this was the work of Russian hackers.

Starring Benedict Cumberbatch (Doctor Strange) and Martin Freeman (The Hobbit trilogy) as the brilliant yet erratic detective Sherlock Holmes and his stoic yet heartfelt assistant John Watson, Sherlock is one of the BBC's most popular exports. The series has aired 13 episodes to date, with "His Final Problem" rumored to be the last, as scheduling the increasingly successful leads actors becomes consequentially more challenging. Once aware of the season 4 leak (h/t Indiewire), the BBC implored fans via Twitter not to share the episode and a spokesperson for the broadcaster stated:

“BBC Worldwide takes breaches of our stringent content security protocols very seriously and we have initiated a full investigation into how this leak occurred,”

The Russian origin of the leak was then confirmed by Sherlock producer Sue Vertue, who tweeted:

"Russian version of Sherlock TFP has been illegally uploaded. Please don't share it. You've done so well keeping it spoiler free. Nearly there,"

Aside from global Sherlock airing network access, a preview screening of the Sherlock season 4 finale episode was held for press and critics in London on Thursday January 12th.

It has been reported that overnight viewing figures for "The Final Problem" reached an all-time low for the series to date. According to this report, 5.9 million tuned in on Sunday night in the UK. This figure does not yet include the undisclosed iPlayer views and cinema screenings, (or global viewing figures) but compared to the 8-9 million views gained by comparable episodes in Sherlock season 3, this is a considerable dip nonetheless.

The availability of a Russian dubbed version of "The Final Problem" is unlikely to have made a particularly large dent in Sherlock's viewing figures, but it is another issue to have dogged this season. The risks taken by the writers to constantly surpass complexity levels and the conflicts created to evolve their beloved characters have been met with trepidation by some fans. Season 4 has faced criticism of its 'Bond-esque' plots and vaingloriously allusive writing.

Despite this, Sherlock is famed for such complexity and the character evolution provided over season 4 was perhaps necessary to prevent its formula from becoming stale and to continue to challenge the show's stellar cast. The various, ingenious twists employed per episode make it imperative the BBC can squash pre-airing spoilers via hackers of any nationality - should the series be secured for possible future seasons.

NEXT: Sherlock Season 4 Finale Explained

Season 4 of Sherlock is now available to view on BBC iPlayer.

Source: Indiewire