Tory leadership: Boris Johnson recruits former party leader Iain Duncan Smith to chair campaign

Heavyweight brought in amid rumours of splits within frontrunner's camp over media strategy and criticism that he has been 'shackled'

Boris Johnson has appointed Iain Duncan Smith as his “campaign chairman”, in a move likely to alarm moderate Conservatives backing his leadership bid.

The decision to pick the former Tory leader and arch-Brexiteer appeared to be a recognition of the need to bring in a heavyweight to bolster the campaign, now under heavy fire from Jeremy Hunt.

No explanation was given, but Mr Johnson’s bid has been disrupted by apparent splits within his camp over media strategy, with criticism that he has been “shackled”.

Mark Fullbrook, a partner with former Johnson adviser Lynton Crosby, has been targeted for mismanaging the transition between the contest moving from Tory MPs to members, The Times reported.

Mr Johnson has made a succession of media appearances over the last 24 hours, after Mr Hunt’s criticism that he was “a coward”, hiding away from scrutiny.

A brief statement read: “Boris Johnson has appointed Iain Duncan Smith MP as the campaign chairman for the membership stage of his leadership campaign.

“He will be working closely with James Wharton [a former Conservative MP] and Mark Fullbrook.”

Mr Hunt has enjoyed a strong start to the second phase of the campaign, likening his rival’s failure to engage with the public to Theresa May's bungled election campaign

in 2017.

Mr Johnson has been thrown on the back foot by his refusal to explain the late-night altercation with his young girlfriend, Carrie Symonds, which led to the police being called to the flat they share.

One poll found his lead among Conservative voters had more than halved since the incident last Thursday – and that Mr Hunt had snatched the lead among the wider public.

More than half of voters said Mr Johnson's private life was relevant to his ability to be prime minister and three-quarters said a candidate's character was relevant to the contest.

The appointment will be seen as a move to firm up support among the European Research Group of hard-Brexit Tories, some of whom spoke out when he wavered on a 31 October departure “deal or no deal”.

Mr Johnson hardened his message again today, vowing to pull out of the EU by that date “do or die, come what may”.

He pledged “positive energy” to deliver Brexit, hitting out at the “pathetic” efforts of Theresa May's administration – a government in which he served as foreign secretary for two years until July 2018.

“I've never seen such morosity and gloom from a government,” Mr Johnson said.

“For three years we've been sitting around wrapped in defeatism telling the British public that they can't do this or that. It is pathetic, it's absolutely pathetic.”