Politicians and commentators have reacted to Boris Johnson winning the Conservative leadership election. While some are optimistic that Mr Johnson will usher in a positive, “can-do” era in British history, others ask whether he has what it takes to deliver Brexit.

Brexit Party leader Nigel Farage said that while he wished Mr Johnson well “with his do or die pledge to deliver Brexit on October 31st”, he wondered whether he has “the courage to deliver”.

Likewise, chairman of the Brexit Party Richard Tice asked: “Can we trust him?”

“Boris is not well known for honouring his word on Brexit, since he voted for the terrible Withdrawal Agreement after calling it vassalage,” he added.

I wish @BorisJohnson well as Prime Minister with his do or die pledge to deliver Brexit on October 31st. Does he have the courage to deliver? — Nigel Farage (@Nigel_Farage) July 23, 2019

Chairman of the Bow Group, the UK’s oldest conservative think tank, Ben Harris-Quinney was cautious over whether he believed that Mr Johnson would deliver Brexit on time, telling Breitbart London: “I believe Boris will do all he can to deliver Brexit. He would be mad not to. Whether he can get it over the line and what sort of country he wants to see post Brexit are the operative questions.”

Nothing in #BorisJohnson's history suggests hes a conservative-He'll likely do all he can to deliver #Brexit-but his vision for the country is likely to be liberal business as usual Cabinet will be real steer & key issues like immigration & culture wars will tell#toryleadership — Bow Group (@bowgroup) July 23, 2019

Continuing on the subject of a Johnson government post-Brexit, Mr Harris-Quinney added: “The Brexit vote was about far more than just leaving the EU, it was about a desire to see a radical shift in the way Britain is governed, a major reduction in immigration, democratisation, and an end to liberal globalism.

“There’s nothing in Boris’s history that suggests he will deliver change to those crucial latter points, and it’s likely on most issues he will be a continuity candidate to Blair, Cameron, and May.”

Time will tell-& if #BorisJohnson governs as a conservative we'll support him wholeheartedly But many will remember #Cameron didn't run as a liberal-he ran on a right wing ticket talking about broken Britain & an end to Blair/Brown 10 yrs later he was indistinguishable to Blair — Bow Group (@bowgroup) July 23, 2019

U.S. President Donald Trump, who has spoken warmly of Mr Johnson previously, wished the future prime minister well, saying: “Congratulations to Boris Johnson on becoming the new Prime Minister of the United Kingdom. He will be great!”

Congratulations to Boris Johnson on becoming the new Prime Minister of the United Kingdom. He will be great! — Donald J. Trump (@realDonaldTrump) July 23, 2019

Outgoing Prime Minister and former party leader Theresa May offered her congratulations, and while Downing Street signalled last month that May would try to frustrate plans for the UK to make a clean break of the EU on October 31st, said on Tuesday that Johnson had her “full support from the backbenches”.

Many congratulations to @BorisJohnson on being elected leader of @Conservatives – we now need to work together to deliver a Brexit that works for the whole UK and to keep Jeremy Corbyn out of government. You will have my full support from the back benches. — Theresa May (@theresa_may) July 23, 2019

While his former opponent Jeremy Hunt said Mr Johnson would “be a great PM for our country at this critical moment”.

Congratulations @BorisJohnson 4 a campaign well https://t.co/b1rmrIHic6'll be a great PM for our country at this critical moment!Throughout campaign you showed optimism,energy & unbounded confidence in our wonderful country & we need that.All best wishes from the entrepreneur :-) — Jeremy Hunt (@Jeremy_Hunt) July 23, 2019

From the backbench Tory Brexiteers, chairman of the European Research Group (ERG) Jacob Rees-Mogg called it a “terrific result” and said it a “great opportunity for the country to make Brexit a success”.

“He will unite the party and the country,” Mr Rees-Mogg told Sky News, adding: “Once we’ve left the European Union, almost nobody will want to rejoin such a failing organisation so it’s a terrific opportunity for unity or positivity for this great nation.”

We look forward to working constructively w/ PM @BorisJohnson when he takes office, to facilitate the ratification of the Withdrawal Agreement and achieve an orderly #Brexit. We are ready also to rework the agreed Declaration on a new partnership in line with #EUCO guidelines. — Michel Barnier (@MichelBarnier) July 23, 2019

Some reaction has also come from the European Union, though comment beyond congratulations are expected on Wednesday, when he is appointed prime minister.

A spokesman for outgoing President of the European Commission Jean-Claude Juncker said: “President Juncker, who is in Malta today, wants me to extend his congratulations to Boris Johnson. The president wants to work with the new PM in the best way possible.”

The EU’s chief Brexit negotiator, Michel Barnier, said he looked forward to working with Mr Johnson to “facilitate the ratification of the Withdrawal Agreement and achieve an orderly Brexit”.

“We are ready also to rework the agreed Declaration on a new partnership in line with #EUCO guidelines,” he added, implying that as far as Brussels was concerned, no new prime minister will change the withdrawal treaty.

Congratulations @BorisJohnson on becoming the next Prime Minister of the United Kingdom. — Ivanka Trump (@IvankaTrump) July 23, 2019

The remarks from Mr Barnier come as it was reported that the European Parliament’s Brexit Steering Group will be meeting with him on Wednesday, likely in light of Mr Johnson’s previous comments that the UK would leave the EU on October 31st with or without a deal.

Incoming Commission president Ursula von der Leyen also hinted at the current tensions between the EU and the UK, but, as expected, called for any outcomes from discussions to be “good for Europe”, saying: “Congratulations to Boris Johnson on being nominated as prime minister and I’m looking forward to having a good working relationship with him.

“There are many different and difficult issues to tackle together. We have challenging times ahead of us. I think it is very important to build up a strong and good working relation because we have a duty to deliver something which is good for people in Europe and the United Kingdom so I’m looking forward to working with him,” she added.

Thank you all for the incredible honour you have done me. The time for campaigning is over and the time for work begins to unite our country and party, deliver Brexit and defeat Corbyn. I will work flat out to repay your confidence — Boris Johnson (@BorisJohnson) July 23, 2019

Mr Johnson made the leadership announcement a family affair on Tuesday, with his father, Stanley Johnson, and sister Rachel and brother Jo present at the QEII Centre in London. The senior Mr Johnson, a self-professed “proud father”, told Sky News when asked how he thought his son would do as prime minister: “He’s going to be fine. He’ll get rid of this small matter of Brexit… and get it done in a flash. I think you will find it will happen very rapidly now.”

During Boris Johnson’s acceptance speech, he pledged to deliver Brexit on Halloween, saying: “I say to all the doubters, dude! We’re going to energise the country, we’re going to get Brexit done on October 31st and take advantage of all the opportunities it will bring in a new spirit of can-do.

“And once again we are going to believe in ourselves and what we can achieve, and like a slumbering giant we are going to rise and ping off the ropes of self-doubt and negativity with better education, more police, and fantastic full-fibre broadband sprouting in every household we are going to unite this amazing country and we are going to take it forward.”