Charlie Gilmour, the son of Pink Floyd\'s David Gilmour, has lost an appeal against his sentence for violent disorder during a student fees protest.Gilmour, of Billingshurst, West Sussex, who swung from a Union flag on the Cenotaph during the demo last December, was jailed for 16 months in July.The Cambridge University student was found to have attacked a shop in Oxford Street and a car in the royal convoy.Judges at the Court of Appeal said his jail term was not \"unduly harsh\".Lord Justice Hughes said the court was unable to say that his sentence was \"arguably either manifestly excessive or wrong in principle\".The history student joined thousands of protesters in Trafalgar Square and Parliament Square, on 9 December last year, to demonstrate against an increase in university fees.Gilmour entered a non-specific guilty plea during a hearing at Kingston-upon-Thames Crown Court.He was found by the judge to have thrown a rubbish bin at a vehicle that was part of a royal convoy carrying the Prince of Wales and Duchess of Cornwall to the Royal Variety show at the London Palladium.He also kicked at the window of Topshop\'s flagship store on Oxford Street and ended up in possession of the leg of a mannequin.The judge in the case accepted the antics at the Cenotaph did not form part of the violent disorder, but described it as \"outrageous and deeply offensive behaviour\".At the Appeal Court hearing, lawyers for Gilmour argued he knew the \"significance\" of the monument but did not realise he was dangling from a war memorial.Lord Justice Hughes, Mr Justice Cranston and Mr Justice Hickinbottom also heard Gilmour had taken LSD and valium before joining the protests.They were told he had \"successfully reformed and rehabilitated himself\" and had addressed the \"underlying drug and alcohol problems\".