The Scottish Football Association is bracing itself for some tough questions after admitting it allowed an assistant referee to officiate in a match when he should have been self-isolating.

Graeme Stewart ran the line in Saturday's Scottish Premiership game between Hibernian and Hamilton despite being a close contact of fellow assistant referee David Roome, who returned a positive test on Wednesday.

Stewart and Roome, along with referee Bobby Madden, had officiated together in Greece last Sunday. Madden was pulled from officiating in Ross County's match against Celtic on Sunday evening at late notice when the error became apparent.

The SFA described the incident as "a breakdown in internal process", and admitted Stewart's appointment contravened Scottish government rules regarding the self-isolation of close contacts, despite Stewart and Madden having subsequently returned negative tests.

SFA chief executive Ian Maxwell said in a statement on Sunday evening: "I have tonight apologised to Hibernian and Hamilton Academical for the unnecessary risk of having an assistant referee at a match when he should have been self-isolating, however much it is mitigated by two negative tests in the build-up to the match.

"As part of an internal review, I have asked the respective departments to ensure we maintain the highest standards of compliance relevant to Scottish Government protocols."

Maxwell confirmed that "no players or members of team staff involved in (Saturday's) match have been identified as close contacts of Graeme".

Hamilton declined to issue an immediate comment on the matter, while nobody at Hibernian was available on Sunday night.