Emmerdale fans claimed to spot a blunder in tonight's episode as Marlon awaits a murder trial in prison.
Marlon is charged with Graham's murder and was recently refused bail by the judge, who said he would face a trial in June.
As innocent Marlon remains in prison, viewers saw him struggle with life behind bars.
Pacing up and down his cell, Marlon was nervous about seeing his daughter April after previously promising her he would come home.
But eagle-eyed viewers claimed to spot a blunder when Marlon look solemnly in a mirror.
Mick wrote: "A mirror in a prison cell?"
Another user said: "Glass mirrors in a prison, I don't think so."
Speaking in an online forum, a ex-convict said that prisoners are only given a small mirror made of plastic on arrival, after full-length mirrors were removed from cells.
*Emmerdale continues at 7pm on ITV on Wednesday
