A high Court judge yesterday said he was "appalled" that prosecutors had brought a case against a teenager for a brutal knife attack to a sheriff court, where the maximum sentence available was five years.

Aidan Riley, 18, was on probation for a violent assault when he stabbed Derek Graham in in Aberfeldy, Perthshire. The knife went through the chest wall, penetrating his left lung and leaving him "lucky to escape with his life".

Yesterday at the High Court in Edinburgh, Lord Uist criticised the prosecutors in the case, saying: "I'm appalled the Crown think this is a suitable case for the sheriff court." Riley was originally accused of attempted murder but the Crown accepted a plea to a reduced charge of assault to severe injury, permanent disfigurement and to the danger of the teenage victim's life, when he appeared at Perth Sheriff Court.

However, Sheriff Robert McCreadie QC decided that his powers of punishment were not robust enough to deal with the offender.

Lord Uist said: "It seems to me to be a wrong decision to indict this attempted murder in the sheriff court. Even on the plea tendered it seems to me to be a High Court case having regard to the accused's background and the nature of the injury. How anyone can take the view attempted murder is worth five years or less I find difficult to believe."

Riley could now face a lifelong restriction order, involving a jail sentence and continuing supervision. Lord Uist said the victim was "lucky to escape with his life" and added if the Crown thought such a case was suitable for the sheriff court he considered "most of the public would disagree".

Derick Nelson, advocate depute, said there was "a great deal of deliberation" over where the case should be heard.

Bill Aitken, Conservative justice spokesman, said he agreed with the judge, adding: "I find it surprising it was indicted at the lower court. The problem in Scotland is serious crime is being devalued. This is deeply regrettable."

Riley stabbed Mr Graham after becoming angry he had been injured during a fight earlier that day. The court heard he took a knife from a kitchen drawer at his mother's house.

Following emergency treatment, Mr Graham had to be readmitted to hospital after he was found to have a litre of blood in his chest cavity. A Crown Office spokesman said: "We will reflect on Lord Uist's comments. We do not normally charge attempted murder in the sheriff court.

"However, the sheriff does, of course, have the power to remit, as has happened in this case, which allows a High Court sentence to be passed on conviction."