In a series of frank admissions Nick Timothy said that his ex-boss and many of her ministers “struggle to see any economic upside to Brexit”.
One of Mrs May’s most influential advisers since her time at the Home Office, Mr Timothy was forced out in 2017 after being blamed by many Tories for that year’s disastrous general election campaign.
He suggested that Mrs May’s approach since then has stopped the Government taking the necessary steps to get the most out of Brexit.
“I think one of the reasons we are where we are is that many ministers – and I would include Theresa in this – struggle to see any economic upside to Brexit,” he said. “They see it as a damage limitation exercise.”
He added: “If you see it in that way then inevitably you’re not going to be prepared to take the steps that would enable you to fully realise the economic opportunities of leaving.”
Mr Timothy addressed the challenges Mrs May has faced in managing her party through the process of EU withdrawal.
“One of the difficulties she’s had is that she’s tried to take every part of the party with her at different points,” he said.
“It would have been better to be clearer that not everybody in the party was going to get what they wanted.”
Mr Timothy, who is a supporter of Brexit, described Mrs May’s premiership as “not bad, but unlucky”. He also said that the UK had made a series of “mistakes” in Brexit negotiations, including letting the EU determine the sequencing of talks, which allowed the £39billion “divorce bill” to be agreed before negotiations on future trade began.
He said the Government should have spent money earlier on preparing for a no-deal Brexit and should have been more “robust” in pushing areas of UK advantage.
He added: “Theresa’s instincts have been that economically, this is a risk to be managed, but politically this is an opportunity and that main opportunity is to recover control of immigration.
“If you look at it like that, then you see why the deal she has negotiated actually makes sense.”
Meanwhile, some Tory ministers are weighing up the “attractiveness” of joining The Independent Group of MPs, it emerged yesterday.
The newly formed political entity was created after the defection of eight Labour and three Tory MPs last week.