Ofcom has ruled that a March 2014 RT programme which included allegations that scenes in the 2013 BBC Panorama documentary Saving Syria’s Children were fabricated breaches the regulator’s broadcasting code.
The RT programme in question – The Truthseeker: “Media ‘Staged’ Syria Chem Attack” – is here:
Ofcom’s decision is here (pp 22 – 49 and 89 – 124).
The website OffGuardian notes some “rather important caveats” in Ofcom’s finding:
Ofcom does not regulate BBC licence fee funded services in respect of accuracy and impartiality and Ofcom has not undertaken an assessment of the accuracy and/or impartiality of the BBC Programmes in reaching this Decision….” – OfCom’s Broadcast Bulletin p. 33 fn.11
Ofcom is not a fact finding tribunal and is not able or empowered, therefore, to establish the truth or otherwise of such allegations and to make findings of fact. Accordingly, it was not possible or appropriate for Ofcom to attempt to prove or disprove the allegations made [by RT] about the BBC in the Programme. Similarly, Ofcom had no statutory jurisdiction to assess the accuracy and impartiality of the BBC Programmes. Rather, our concern in this case was solely whether, taking account of Section Seven of the Code, the Programme had resulted in unfairness to the BBC. – op. cit p. 115
Quoted in this online BBC News report published on 21 September 2015, TV Novosti, RT’s owner, maintains that the BBC footage in question “clearly was faked” and that “any damage to the reputation and good name of the BBC [was] self-inflicted”. A press statement from the broadcaster is here.
OffGuardian observes that Ofcom’s finding “has been trumpeted by the Beeb itself and other mainstream outlets as a ringing vindication of BBC editorial standards”. This view is borne out by reports from the BBC, The Independent and The Guardian (I have commented below the Independent and Guardian pieces as “cerumol” ) and the tweets from corporate journalists reproduced below.
RT has further defended its report in this editorial of 3 June 2017 (relevant excerpt reproduced below).
The report was briefly discussed by Andrew Neil and RT.com journalist Afshin Rattansi on an edition of BBC’s This Week (from 5 minutes 48 seconds). 
Rattansi was confronted again about the RT Truthseeker report in this 2018 Radio 4 Today interview with John Humphrys (from 1 minute 50 seconds):
 As of at least January 2017 my comment below The Independent article is no longer visible.
 Neil is correct that RT claimed the BBC staged a chemical attack, but incorrect that RT “digitally altered” words: this was RT’s (accurate) claim against the BBC. My view on the relevance of this alteration is addressed in footnote  above.