Anyone in England and Wales with a dog out of control can now be jailed for six months. If the dog causes injury, the maximum term is to be two years. I have no sympathy for such people. Keeping these beasts is weird, and those who do it probably need treatment. But the Defra minister, Lord Taylor of Holbeach, complained in May that fewer than 20 people were in jail for dangerous dog offences. The sentencing council has duly told courts to raise the threshold to two years, "to send a message".

The same sentiment a year ago motivated magistrates to play to the gallery by jailing 1,292 people for stealing bottles of water or trainers or sending idiot incitements during the dispersed rampage dubbed "urban riots". Hysterical ministers raced home from holiday to tell judges to send messages. Judges duly ruined the lives of hundreds of young people, at great public expense and to no advantage to their victims. I have no sympathy for these people either, but again the politicised response to crime was disproportionate.

A month before, a London court jailed a stoned Charlie Gilmour after he swung on a union flag from the Cenotaph and tossed a bin at a police car, thus causing widespread outrage in the offices of the Daily Telegraph and Daily Mail. The judge sent him down for 18 months to send a message carefully designed to wreck his university career. Yet again we need have no sympathy for Gilmour. But there is no such thing as a rap over the knuckles in jail. Judges know that any term in prison is a sentence for life.

How can British politicians, whose statements clearly seek to influence pliable judges, criticise other sovereign states for doing likewise? Last week the Foreign Office professed itself "deeply concerned" at the fate of Russia's Pussy Riot three, jailed for two years for "hooliganism" in Moscow's Christ the Saviour Cathedral. They had staged what, by all accounts, was an obscene publicity stunt, videoing an anti-Putin song defamatory of the Virgin Mary in front of pious worshippers.

Good for free speech, we might all say. That the act outraged public decency is an understatement. In a Levada poll of Russian public opinion, just 5% thought the girls should go unpunished and 65% wanted them in prison, 29% with hard labour. Artists round the globe may plead free speech, but to treat the Pussy Riot gesture as a glorious stand for artistic liberty is like praising Johnny Rotten, who did similar things, as the Voltaire of our day. There can be disproportionate apologias as well as disproportionate sentences.

Artists can look after their own. For the British and US governments to get on high horses about Russian sentencing is hypocrisy. America and Britain damned the "disproportionate" Pussy Riot terms. In America's case this was from a nation that jails drug offenders for 20, 30 or 40 years, holds terrorism "suspects" incommunicado indefinitely and imprisons for life even trivial "three strikes" offenders. Last week alone a US military court declared that reporting the Guantánamo Bay trial of Khalid Sheikh Mohammed would be censored. Any mention of his torture in prison was banned as "reasonably expected to damage national security". This has no apparent connection to proportionate punishment or freedom of speech.

The British security establishment during the Tony Blair-Gordon Brown regime tried to censor history books for possible "terrorist" incitement. It introduced control orders, restricted courts and long-period detention without trial. It made unlicensed demonstrating an offence and has since sought prosecution of Twitter and Facebook abuse. British ministers and courts are craven to what passes for public opinion. The idea that, whenever a crime or antisocial action hits the headlines, "the courts must send a message" is politicised justice. At times, especially in tragic cases involving children, it gets near to a lynch mob. Again the only message sent is to the media. If Britain's draconian sentencing were effective, British jails would not be bursting at the seams.

There is of course a difference between the liberties enjoyed in most western democracies and the cruder jurisprudence of modern Russia, China and much of the Muslim world. It would be silly to pretend otherwise. But the difference is not so great as to merit the barrage of megaphone comment from west to east. Pussy Riot may have attacked no one physically, but no society, certainly not Britain, legislates on the basis that "words can never hurt". If a rock group invaded Westminster Abbey and gravely insulted a religious or ethnic minority before the high altar, we all know that ministers would howl for "exemplary punishment" and judges would oblige.

Commenting on the social mores of other countries may offer an offshore outlet for the righteous indignation of politicians and editorialists. It has no noticeable effect. Western comments on the treatment of women in Muslim states, dissidents in China or drug offenders in south-east Asia are dismissed as imperial interference. But then how would we feel if Moscow or Singapore or Tehran condemned the treatment of Cenotaph protesters?

British courts jail at the drop of a headline. One of the few cabinet ministers in recent years to show a sincere desire to relate punishment to crime and imprisonment to consequence is the justice secretary, Kenneth Clarke. He is now being bad-mouthed out of his job by Downing Street's dark arts, frightened not of Clarke but of the rightwing press. Clarke is, with Iain Duncan Smith, a rare minister intellectually engaged with his job and eager courageously to see it through. Why are the Lib Dems not defending him? For David Cameron to sack Clarke would indeed send a message. Of the worst sort.