In its attempt to continue lawlessly spying on almost everyone, Britain’s “intelligence” and “security” establishment has launched an assault on the Guardian. Such is the rise of the totalitarian state that the secret police enter a newspaper to witness the smashing of computer hard drives, as happened at the Guardian, and the government, via a poodle MP, can call for the paper’s prosecution for treason. As if to prove its respectability, the Guardian has sought the endorsement of notables, including Nick Clegg, Harold Evans and other specialists in faint praise.

The most effective defender of the paper is not one of these. He has shaggy, dark hair and a beard – or he did when I last saw him. For more than 20 years I have reached for his work as you do for a first cup of coffee. He is outrageous, anarchic, brilliant, sometimes inexplicable and a bit mad (not really). For those who doubt the truth is subversive and often absurd, I point them towards two pages in the Guardian where he resides.

Only Steve Bell exposes consistently, fear lessly, the bullshit of “public life”. Indeed, his characters are often drowning in or waterskiing on the stuff. “Right! That’s it!” says the last governor of the Bank of England, Sir Mervyn King, to Gordon Brown, then prime minister, and Chancellor Alistair Darling. “Heads down, tea break over!!” They are up to their chins in a tank of turds.

Steve Bell is a cartoonist and a true journalist with few rivals. He is Hogarth and Swift with a touch of Peter Sellers and a sprinkling of Orwell. He is more of an English original than one of his prime targets, Margaret Thatcher, the former petit-bourgeois totem. Often using the wickedly all-seeing star penguin of his strip “If . . .” he rumbled both Thatcher and her protégé Tony Blair early in their criminal ascendancy.

While his Guardian colleagues swooned over Blair as a mystic of the “Third Way”, Steve Bell planted Thatcher’s crazed eye on Blair’s rictus mask. A print of that first appearance of the Thatcher/Blair eye, which he sent me, hangs in pride of place at home, though the gaze is disconcerting. Opening the Guardian news pages recently to find Blair boasting about his ability to absorb “the sense of pain” felt by others was like reading a Steve Bell cartoon.

If there was an authentic free press in Britain, newspapers would do as Steve Bell does; they would tear down the façade of a system in which the political parties have converged and democracy is a propaganda term. Labour is a conservative party whose new shadow minister for work and pensions, Rachel Reeves, formerly of the Bank of England, says an Ed Miliband government will be tougher than the Tories in cutting the benefits of ordinary people. Tristram Hunt, the new shadow education minister, says he “will not prevent” the opening of privatised schools. They are managerial Tories. Steve Bell refuses to play their game, which is designed to confuse and demoralise voters, especially Labour voters.

Unclubbable and unpredictable, he shines a white light on such betrayal and hypocrisy. He depicts all our rulers with the hilarious equanimity of his savagery. David Cameron, the former PR spiv, is perfect pink in his condom; Jack Straw, he who covered up the lies of Iraq and approved incarceration in Guantanamo, is sinister in outsized pebble glasses; Gordon Brown blusters about ending poverty while crawling into the colonic regions of the City’s fattest cats; and Clare Short. Ah, Clare Short. In 1999, having promoted herself as a feminist-of-the-people and Labour dissident, Short became one of Blair’s keenest warmongers in his “crusade” in the Balkans, the harbinger of his bloodbath in Iraq. The Nato bombing that triggered a human stampede and destroyed much of Serbia’s infrastructure launched Steve Bell’s inspired “armchair warriors”.

Flying across Balkan skies, formations of armchairs approach their targets: “We’re coming in, victorious . . . but eschewing triumphalism . . . you’d better believe it, Serb suckers!” In one large armchair sits Short: “I think the time has come,” says she, “for Pilger and his ilk . . . to show a little humility . . . and apologise for being so wrong . . .” Short, the then minister for international development had likened those who challenged the fraud of Blair’s war to Nazi appeasers. Steve Bell honoured her with a strip entitled “Armchair Cleansing for Beginners”.

Steve Bell was one of the first to expose New Labour and to satirise its creator, Peter Mandelson. “What are you doing up the tree, master?” asks the dog. “I am Man-dee, the one-eyed trouser snake . . . I am the keeper of the tree of New Labour knowledge. I know where the bodies are buried . . . I can destroy the Labour Party . . . Unless I am given an important cabinet post with immediate effect!!”

Visiting a comprehensive school, the disapproving education secretary, David Blunkett, demands “value-driven, faith-based targets . . . otherwise the [seeing-eye] dog gets it”. The headmaster, who happens to be the ubiquitous penguin, obeys and launches a new curriculum with this maths test: “Sixteen bishops are travelling to Synod. Six and a quarter per cent of them are arrested for indecent assault. How many bishops go free? You may use tambourines.”

As the Guardian has published Edward Snowden’s revelations and so drawn the ire of the Daily Mail, Steve Bell has welcomed the Mail’s editor, Paul Dacre, into the dungeons of his “If . . .” strip. Resembling Sellers as Dr Strangelove, Dacre demands “ein bonfeuer of der red tape und der red everything!”. Even his proprietor, Lord Rothermere, looks alarmed, while the hollow-eyed death mask of Rupert Murdoch yells: “Free priss! Burn the tiny liftist Guardian!”

In the current issue of the Journalist, there is a Steve Bell cartoon that may turn out to be the image of our time – a journalist at work on his computer with a large jackboot bursting through the screen. Reminiscent of E H Shepard’s Punch cartoon “The Goose-Step” (1936), which famously warned of the rise of fascism, it is brilliant and not funny.