Pink Floyd guitarist David Gilmour's son lost an appeal today against his 16-month sentence for going on a drink and drug-fuelled rampage at a student fees protest.
History student Charlie Gilmour, 21, of Billingshurst, West Sussex, who admitted violent disorder after joining thousands demonstrating in London's Trafalgar Square and Parliament Square last year, had his challenge rejected by Court of Appeal judges.
Lord Justice Hughes, announcing the decision in London, said the court was unable to say that his sentence was "arguably either manifestly excessive or wrong in principle".
The Cambridge University history student, who was sentenced in July, was seen hanging from a Union flag on the Cenotaph and leaping on to the bonnet of a Jaguar car that formed part of a royal convoy.
Gilmour was found by a judge at Kingston Crown Court, south west London, to have thrown a rubbish bin at the vehicle.
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 at Kingston accepted that the antics at the Cenotaph did not form part of the violent disorder, but described it as "outrageous and deeply offensive behaviour".
During a recent hearing before Lord Justice Hughes, Mr Justice Cranston and Mr Justice Hickinbottom, his barrister told the judges that Gilmour was intoxicated and did not realise he was swinging from the Cenotaph.
The Crown Court heard that he had turned to drink and drugs after being rejected by his biological father, writer Heathcote Williams, and had taken LSD and Valium in the hours leading up to the violence.
Appeal judges heard that he had "successfully reformed and rehabilitated himself" and, in particular, had addressed the "underlying drug and alcohol problems".
Gilmour's parents did not attend the Court of Appeal for today's announcement.
Lord Justice Hughes said Gilmour's offence was committed in the centre of London "in the course of serious disorder which occurred in the later stages of what had begun as a generally peaceful demonstration against Government proposals relating to the funding of further education".
There was, he said, "serious mob disorder".
He said: "The defendant admitted violent disorder. He was unmistakably captured on CCTV footage in Oxford Street joining in the attack on the windows of a shop.
"He was part of a violent crowd laying siege to the shop, in which both staff and shoppers were trapped.
"He twice ran up and launched heavy kicks at the window, as did others before him and, no doubt, after him.
"The combined effect of the attack was that the windows were at some stage broken - it may well be by the time the defendant joined in.
"The defendant helped himself to a section of a mannequin and carried it away."
Lord Justice Hughes said the Crown's case was that Gilmour also took violent part in the attack on the royal cars a little earlier.
There was evidence that Gilmour was "quite significantly under the influence of both drink and drugs that day".
At times during the day he was clearly "in good, if intoxicated, humour". In Parliament Square earlier in the day "he can be seen shouting good-humouredly and at another point declaiming poetry".
The judge said: "Unfortunately, however, his behaviour was not always in this benevolent category."
At one point "there is no doubt that he crouched down in the doorway of the nearby Supreme Court and tried to set fire to a bundle of newspapers against the wooden doors", but was "dissuaded and scampered away".
Lord Justice Hughes added: "That cannot have been other than potentially very dangerous and, in the context of a volatile crowd, very likely to lead others to behave equally dangerously."
He went on: "A little later he was to be found swinging in an exhibitionist manner and for quite a prolonged period on one of the flags on the Cenotaph.
"This was an incident which, unsurprisingly, subsequently attracted a good deal of attention.
"Deeply offensive as it undoubtedly was, it did not amount to violence and thus was not part of the offence of violent disorder with which he was charged.
"Its relevance in law is limited to the fact that, along with the other behaviour, it demonstrates that he was at times over-excited, out of control, and raising the temperature in a manner which could only be dangerous in the context of a large and angry crowd."
The judge at Kingston concluded that he was sure Gilmour had thrown a bin at a car in the royal convoy - which had been conveying the Prince of Wales, the Duchess of Cornwall and others to an evening public engagement.
The appeal judges ruled that he was "entitled to come to the conclusion which he did".
Lord Justice Hughes said of Gilmour: "He is plainly a talented man."
References from people who knew him well described him as a person who is "generally of gentle and peaceable disposition".
He said the judge at Kingston "rightly treated what the defendant did as entirely out of character".
The appeal judges agreed with Gilmour's barrister that testimonials from a national charity for the homeless painted a "picture of his capacity to behave very differently" from the way he did on December 9 last year.
He had earned "considerable praise for respect for others, long hours, reliability and enthusiasm".
It was also clear, said Lord Justice Hughes, that "he has been much chastened by the realisation of what he did".
He added: "He has made genuine efforts to stop drinking and taking drugs. He made a public apology soon after the event, stimulated no doubt by the heavy publicity which the graphic pictures of the Cenotaph incident had generated."
The law protects the right of people in this country to demonstrate - to "make known and in public their feelings on matters of public concern" - but to do so in large numbers in public "carries clear responsibilities, principally amongst them to act without disorder or violence which puts the public at risk".
The attack on the shops in Oxford Street "was an attack by a mob on hapless shoppers and staff who were terrified as well as trapped inside, whilst the attack on the cars was upon both public figures and those whose job it was to protect them".
Lord Justice Hughes said: "It is an unavoidable feature of mass disorder that each individual act, whatever might be its character taken on its own, inflames and encourages others to behave similarly, and that the harm done to the public stems from the combined effect of what is done en masse.
"We do not believe that violence in this context and of the kind displayed by this defendant can normally be met by other than significant sentences of immediate custody even for those of otherwise good character."
The sentence passed by the judge "correctly took account both of the defendant's serious and dangerous acts in this inflammatory context and of his normal character".
Lord Justice Hughes said the sentence was a "penalty which properly met the facts of this case".