A “gutted” Eve Muirhead appeared to question the voided final stone which saw Great Britain fall to a 8-6 defeat to Sweden in the round robin phase on Sunday.

Britain trailed 6-4 going into the ninth end but levelled to take the match to an extra end. The Swedes had the advantage of the hammer but Muirhead had the chance to make it difficult for them with Britain’s final stone. But the stone was voided, leaving the Swedes the simple task of clinching victory with the hammer.

It was not immediately clear if Muirhead had been penalised for not releasing the stone clearly before the red line – known as hog lining – or whether she touched the stone twice leading to her being penalised. Either way, her final stone was taken off the rink leaving the Swedes to wrap up the win with the hammer.

She later tweeted a photo of the incident which showed her hand was clear of the stone and the stone was behind the line.

Muirhead said: “The red light came on so that’s counted as a hogged rock, so that has to be taken off. When you see the replays in the stadium it looks like it was. It’s hard to take and it comes down to inches and millimetres.

“It’s the first stone I have ever hogged in my life and when it comes at a time like that. We have had the stone tested and it’s fine so there’s nothing we can do, we have to move on. It’s the story of our week so far. When something like that happens it makes it very tough to take and it’s gutting that it finished that way.”

Coach Glenn Howard added: “I’ve only seen one replay and it looks like Eve has let go of the rock prior to the hog line and the light went off. It’s a horrible way to finish the game. I’ve never witnessed Eve Muirhead have a hog line violation ever.”

The defeat leaves Muirhead’s rink with three wins out of six so far – the same as the men’s team featuring her brothers Thomas and Glen, who needed an extra end to defeat Denmark 7-6 on Sunday evening.

The men’s team faced their own minor controversy during their match as the extra end was temporarily paused to discuss the fate of a ‘burnt’ stone – one accidentally touched by a member of the opposing team.

Canadian women’s skip Rachel Homan was heavily criticised on Friday for going against curling etiquette for removing a ‘burnt’ stone from play during her defeat to Denmark. On this occasion, GB men’s skip Kyle Smith consulted an umpire before agreeing with the Italians to slightly nudge the stone back to reflect the impact of intervention.

Smith said: “I didn’t see it at first but he (an Italian player) told us he’d trapped the stone on the side with his foot so I think you just have to do what is right in the moment.

“We asked the umpire what our options were and we thought it was right to leave the stone on. I’m pleased with how we handled the situation – it can knock your confidence because it doesn’t happen often.”