John Bercow’s gift for giving unnecessary offence has throughout his life placed him in dangers a more prudent person would have avoided. At school he goaded the bullies who attacked him, with the result that their cruelties became more insistent. As a Conservative MP he tended to insult whoever became party leader, with the result that his front-bench career soon ended in failure. As Speaker, he has this summer provoked such wrath among parliamentarians, by attempting to place an unqualified Australian in the post of Clerk of the House, that he has endangered his own position.

But it would be a pity if his faults of character were allowed to obscure the abilities which make him one of the best Speakers of modern times. As Jacob Rees-Mogg (Con, North-East Somerset) puts it: “His good qualities hugely outweigh his bad qualities. I’m very much a supporter because he stands up for the legislature against the executive.” Since Bercow arrived, ministers have been forced to come far more often to the Chamber to justify themselves. This is not convenient for the Government, but it is an excellent thing for Parliament. And one may doubt whether under an emollient Speaker it would have happened to anything like the extent that it has happened under Bercow.

Bernard Jenkin (Con, Harwich and North Essex), who chairs the Public Administration Select Committee and has been in the House since 1992, said: “Speaker Bercow has on balance been a good Speaker and an excellent presiding officer who has brought the House to life and empowered backbenchers. He found himself this week in a very difficult position and he behaved politely and gracefully in the face of intense provocation. The idea that because one or two MPs shout ‘Ha’ his credibility is shot and he should be thrown to the media wolves is just irresponsible.”

Jenkin made these comments before Bercow’s slightly less polite and graceful response to the three Conservative backbenchers – Simon Burns, Michael Fabricant and Christopher Pincher – who put points of order to him yesterday, immediately after Prime Minister’s Questions. Those three spoke for the irreconcilable haters of the Speaker on the Tory benches: Burns once had to apologise for calling him “a stupid, sanctimonious dwarf”. They are convinced that he is unfair to the Tories, they are not prepared to give him any credit for keeping a healthy distance from the Government, and they hope if they go on annoying him they will one day cause him to explode. But the trio did not speak for all Tory MPs: Sir Edward Leigh rose immediately after them to observe that if a democratic assembly is to function properly, “it is absolutely vital to uphold the authority of the Speaker”.

Watching from the press gallery in the summer of 2009, one saw an immediate and dramatic improvement when Bercow took over from Michael Martin, who was ejected from the Speaker’s chair after being found out of his depth during the expenses scandal. Under Speaker Martin, the House spent somnolent afternoons when things seemed to have come pretty much to a standstill. Under Speaker Bercow, it became usual to get through the questions on the Order Paper, and ways were found to debate whatever subjects had suddenly become topical.

Yet like some Tory backbenchers, some journalists found they could not bear Bercow. The best known of these, Quentin Letts of the Daily Mail, publishes quite frequent denunciations of the Speaker in which he accuses him of being irrational and yobbish, and destroying the dignity of his office.

One can see what Letts means. In an ideal world, one can imagine a Speaker clad in the traditional robes and wielding such moral authority that he or she quells Burns, or indeed more formidable figures than Burns, with a raised eyebrow. But on stormy days in the Commons, even the Archangel Gabriel’s raised eyebrow might prove inadequate. And even supposing such a paragon could be found, and could gain election, he or she would very soon be attacked as an Establishment stooge, out of touch with modern Britain, nothing like independent-minded enough, quite incapable of fighting for backbenchers’ rights, the sort of person who tries to smooth over every difficulty by appealing to an obsolete code of manners, bring back Bercow, he may have been a bit of a hooligan but at least he loved having an argument and was able to think on his feet.

Bercow’s willingness to fight his own corner, indeed his inability not to fight it, emerged at an early age. I am indebted for what follows to Bobby Friedman’s biography, which is well-researched, though not, unfortunately, well-written. At Finchley Manorhill, his north London comprehensive school, Bercow became the most unpopular boy in his year. He was small and his face was covered in acne. He was plainly very clever, but he wasn’t clever about the way he handled being clever:

“He often flaunted his superior ability…Perhaps trying to compensate for his size, Bercow would often try to humiliate bigger kids in his class. One in particular used to make mistakes with his reading and Bercow would write them down and recite them back to him. Incidents like these would certainly have contributed to the view that Bercow was ‘an odious little toad’.”

One of his habits as a small boy was to sit on the wall outside his parents’ house, almost hidden by the copy of The Times which he was reading. For although Bercow would describe himself as a moderniser, he is in some ways a very old-fashioned one, with a love of orotund 19th-century language. He enjoys imitating politicians who speak in an elaborately antiquated manner: Sir Peter Tapsell, say, or Michael Gove.  A neighbour said of him as a child:

“He was very precocious. He had a fabulous brain, but tended to discuss with you what your faults might be and in the end you just gave him a wide berth. He looked down on everyone and was determined to be running the country. He told me one day he would be an MP and in the Cabinet.”

Bercow’s paternal grandfather, Jack Bercowitch, was a Jew from Romania who arrived in London at the age of 16, in 1900, worked first as a gas fitter and then as a furrier, and in due course opened a shop. Two of his sons, Ralph and Charlie, set up a business called Bercow Motors, in Warren Street in central London, which prospered until the late 1960s, when the council painted yellow lines on the road outside their showroom. Charlie Bercow married Brenda Bailey, a legal secretary who was not by birth Jewish, and in 1963 she gave birth to their son, John Simon Bercow. So when Bercow describes himself as “the Jewboy son of a taxi driver”, this is, as Friedman observes, “something of an over-simplification”. It would be more accurate to describe him as the son of a small businessman, which is probably one of the things that made him a natural Conservative. But when he was still quite young Bercow Motors did indeed close down, his parents got divorced, and his father started driving minicabs.

The young Bercow was the best under 12 tennis player in Middlesex, but got left behind when his opponents grew and he didn’t. His other passion was politics: his local MP was Margaret Thatcher and he delighted in defending her policies to hostile audiences. He joined not only the Young Conservatives but the Monday Club, where very soon he was promoting the voluntary repatriation of immigrants. His admiration for Enoch Powell was unbounded. He began life with no influential connections, and with a thin skin which perhaps accounts for most of his rudeness, but with the energy, ambition and ability to go a long way.

He went first to Essex University, where he took a first-class degree in government and politics. He also became deeply involved in the Federation of Conservative Students, where Paul Goodman described him as a “pocket Cicero”. Bercow was elected Chairman of the FCS, prior to a titanic bust-up when he sided, with what struck his friends as unnecessary emphasis, with Norman Tebbit, the Conservative Party Chairman, against Harry Phibbs, who had published an article declaring Harold Macmillan guilty of sending 40,000 Cossacks to their deaths.

For a man who had set his heart on becoming a Conservative MP, this was the right decision. When he wished to charm local Conservative associations, he could do so. But Bercow was made to work his passage: in 1987, he was defeated in the hopeless Scottish seat of Motherwell, and in 1992 he lost in Bristol South, to which as candidate he had devoted three years of weekends. In 1997, he was elected for the safe seat of Buckingham.

He at once became a manically active speaker in the Commons, and also an assiduous heckler: he has since conceded, or boasted, that during his first five years as an MP, “my behaviour was spectacularly bad – I mean not just sort of bad but bad on an industrial scale”. In the parliamentary session which ended early in 2000, Bercow made 76 speeches, more than any other Member and well ahead of Eric Forth, in second place with 57. He had become one of the relatively small number of MPs who keep the Chamber alive. In my view his remarkable enthusiasm as a backbencher for taking part in debates is one of his greatest qualifications for the Speakership.

His manners remained poor: Bercow enjoyed being extraordinarily rude about people. But a key element in our tradition of free speech is the right of obscure people to be as rude as they like about the prominent. Bercow denounced Cherie Blair as an “unaccountable cross between First Lady and Lady Macbeth”.

Quite soon he began attacking members of his own side. Bercow was clearly moving towards the Labour Party. He was one of the first of the 1997 intake to be promoted to the front bench, and one of the first to be sacked. Michael Howard got rid of him after Bercow congratulated Tony Blair for giving a “superb speech in the Iraq debate”, in which Howard himself was not reckoned to have done well.

A worse misjudgement was to follow. During the 2005 Tory leadership campaign, Bercow not only backed Ken Clarke – in itself an understandable preference – but launched a caustic attack on another of the candidates, David Cameron: “In the modern world the combination of Eton, hunting, shooting and lunch at White’s is not helpful when you are trying to appeal to millions of ordinary people.”

Cameron, who was very angry to find class war being waged against him by a member of his own party, surprised almost everyone by winning the leadership election. Bercow’s chances of advancement as a Conservative were now close to zero, especially as he had married a wife, Sally, who had become a strident Labour supporter.

He gambled instead on becoming the next Speaker, and when the expenses disaster did for Speaker Martin, a working-class Labour MP from Glasgow, Bercow seized his chance. As a Labour whip explained: “The Tories have tried to stuff us by taking down one of ours. So we’re going to stuff them by voting for someone they hate. But they can’t complain; John Bercow is a Conservative MP, if only nominally.”

Bercow played the class war card: “For far too long the House of Commons has been run as little more than a private club by and for gentleman amateurs.” If he had not believed this, his words would have sounded like mere posturing. But this gifted outsider with a phenomenal memory, who could recall the name and birthday of everyone in the House, and had been spurned by his own side, quite clearly did believe it. He also commended himself at this time to a large number of MPs by having been no angel as far as his own parliamentary expenses were concerned, and by indicating that he would do what he could to soften the austerities of whatever new expenses system was introduced.

I realise that many readers will regard this account of Bercow’s career as clear evidence that he is not fit to be Speaker. If the House had wanted to take a Speaker from a traditional background, who would behave with traditional circumspection, then Sir George Young would have won the election in 2009, and would undoubtedly have proved a very good, impartial, affable, judiciously modernising figure.

But the House, or the greater part of it, wanted a less tactful Speaker, who was himself an outsider, and would be less respectful of long-established ways of doing things. Hence the row about the appointment of the next Clerk of the House. Bercow is plainly not all that impressed by the pedantic expertise of the Clerks, and not as grateful as he might be for the help they gave him when he got things moving again in the summer of 2009. The likelihood is that they have often acted as a necessary check on his power. But even Sir Robert Rogers, the generally admired Clerk of the House who has just retired, recognised, in Order! Order!, a parliamentary miscellany which he published in 2009, that the mentality of a Commons Clerk is likely to be quite odd. The book includes an apocryphal advertisement for the Clerk of a Select Committee:

“Committee of MPs seeks thwarted academic, capable of being decisive – in different directions and on the same day if necessary. Should be of resilient character, capable of reconciling the irreconcilable. Should exhibit judgement when confronted with insanity, and undoubted, but well-hidden, powers of intellect and persuasion. Ability to produce the appearance of order and procedural rectitude out of complete chaos desirable.”

Bercow thought various other things were desirable. But as so often, he showed an excess of zeal, and promoted the cause of a woman from the other side of the world who possesses none of the knowledge of Commons procedure which a Clerk simply has to have. He pushed his personal candidate, got found out, and on Monday began the retreat he must make in order to save and re-establish his own position.

MPs who value the office of Speaker are anxious to help him to make that retreat. For most of them recognise that to get into the habit of sacking the Speaker every few years would be destabilising, and would make it harder for any future holder of the office to command authority. The charge is sometimes made against Bercow that he cares more about himself than about the institution which he serves. But this is a charge which can also be made against his critics: that they are so blinded by their personal hatred of the Speaker, they forget the respect which is owed to his office.