Pennell stabbed Luke Walmsley through the heart in front of pupils

Luke Walmsley, 14, was stabbed through the heart by Alan Pennell at Birkbeck College in North Somercotes, Lincolnshire, November 2003.

Pennell, 16, was detained for life for murder and ordered to serve at least 12 years behind bars.

The Appeal Court ruled the minimum term given in July was "appropriate".

Pennell was found guilty following a trial at Nottingham Crown Court.

Luke Walmsley was stabbed in the heart at school

Patricia Harding, representing Parnell at the London Court of Appeal on Wednesday, claimed too much account was taken of the crime's background when the minimum sentence was set.

She disputed the fact the stabbing was committed inside school premises and against a fellow-pupil were genuinely aggravating factors.

Lord Justice Rose was sitting with Mr Justice Mackay and Mr Justice Douglas Brown.

Lord Rose said: "The fact that this stabbing occurred in school when there were other teenage children - and perhaps younger children - around, was a matter to which the judge was properly entitled to have regard."

Luke was stabbed with a flick-knife in the school corridor after he and Pennell, then 15, emerged from their morning class.