Far from uniquely in Westminster, Gavin Williamson’s self-image doesn’t always accord with how others see him. The 41-year-old defence secretary cultivates the aura of a modern-day Machiavelli, with a pet tarantula in a tank in his office signifying a ruthless approach to his enemies.

The biggest noise he has made so far at the Ministry of Defence was his blood-curdling call for the deaths of British citizens who travelled to Syria to fight for Islamic State. It is arguably illegal, but it was a politically astute suggestion, pleasing voters on the right. He is the proud owner of a Falklands war-era Land Rover, which “epitomises everything that is so fantastic about Great Britain: a go anywhere do anything attitude”.

In his maiden speech as MP for South Staffordshire in June 2010, he announced himself as “a straight talker” and urged the country to rediscover “the Victorian spirit of ingenuity and inventiveness”. His antennae are well-tuned to the interests of the readers of the Sun and the Daily Mail. One acquaintance described him as “sociable and free of the superior air of so many Tories”.

Understandably, the married father of two’s rapid rise from backbencher via the whip’s office to defence secretary in just seven years has seen his confidence soar. But some see him as slightly comic; an over-promoted upstart out of his depth in one of the biggest offices of state.

When Theresa May appointed him to defence following the resignation of Michael Fallon after a sexual harassment scandal, the Conservative backbencher Sarah Wollaston remarked: “There are times when offered a job that it would be better to advise that another would be more experienced and suited to the role.”

Even Williamson himself admitted to his local newspaper that he was “flabbergasted” to be offered the job by the prime minister, something critics took with a pinch of salt, suspecting that he had knifed Fallon to win the office for himself.

Soon after, he clashed with Philip Hammond in the House of Commons over a briefing from an ally of the chancellor that compared the defence secretary to Private Pike, the weedy character in the BBC comedy Dad’s Army.

As people rushed to find out who he was – there was reportedly some frantic Googling in the MoD – those looking at his social media accounts compared him to Steve Coogan’s comic creation Alan Partridge.

Posts on Williamson’s Instagram feed include: “Very pleased with my new garden incinerator only £14.99 from #aldi, cracking good value. Question is could we make use of one in the whips office?” and “You can’t beat a small treat such as Car magazine. Much cheaper than actually buying a new car.”

Kate Moody, who sold him the tarantula, told BBC Radio 4: “He said it may have been a midlife crisis. It was a sports car or a tarantula and the tarantula won.”

Williamson was born in Scarborough, North Yorkshire in June 1976 to Labour-voting parents, Ray and Beverley. He went to comprehensive school before studying social science at Bradford University. In 2001 he married Joanne Eland and worked managing a pottery in Staffordshire and then an architectural design firm.

He was elected to Staffordshire county council aged 25 and then in 2005 – still not 30 – failed in his first parliamentary election. He was elected at his second attempt and after roles as parliamentary private secretary to several ministers he was selected for the same job by David Cameron. He voted for remain in the Brexit referendum, partly out of loyalty to Cameron.

After he ran May’s leadership campaign she appointed him chief whip and he was “brilliant”, according to Nick Timothy, May’s former chief of staff. Williamson was pivotal in the deal struck with the Democratic Unionist party to keep the Tory minority government in power and May “rated him”, said Timothy.

He arrived at the MoD in November just as the military was facing cuts including a reduction in the size of the army and the reduction of some assault ships.

“He was dealt a really hard hand being brought in without any experience at the tail end of a defence review,” said a senior defence industry insider. “He came in not really understanding what it all meant apart from it was bad news politically. Quite a number of Conservative MPs were up in arms about [the cuts].”

But Williamson sees how the role can further his own ambitions, say observers, especially if he can secure extra defence funding, with figures, including Michael Gove, considering him a contender for the party leadership.

“He’s not a traditional Conservative,” said the defence insider. “He doesn’t have a public school background. He is from a middle-class northern background which is what the Conservatives need more of.”

• This article was amended on 29 January 2018. An earlier version said Scarborough was in east Yorkshire. It is in North Yorkshire.

