EU welcomes Johnson by rebuffing his Brexit plans

French president Emmanuel Macron and the next president of the EU commission, Ursula von der Leyen, immediately congratulated Johnson, and said they looked forward to constructive talks with him.

"I'm looking forward to having a good working relationship with him," von der Leyen told a joint news conference with Macron in Paris.

"We have the duty to deliver something which is good for people in Europe and in the UK," she said.

Von der Leyen has earlier stated that she would be open to an extension of the Brexit deadline, currently 31 October, but that would have to be decided by EU leaders at their summit in mid-October.

While EU leaders want to avoid a no-deal Brexit, most of them are frustrated with the ongoing political crisis in the UK.

Macron said he hoped to work "as soon as possible" with Johnson, not just on Brexit but also other international matters such as Iran.

Macron was a vocal opponent to an earlier extension granted by the EU to the UK at a previous EU summit earlier this year.

Macron also sent a warning to Johnson when he pointedly praised outgoing UK prime minister Theresa May for never "blocking the workings of the EU".

"She tried to best serve the interests of the British people, and in a very loyal fashion," Macron said.

'Can do'

Johnson, who has long cherished an ambition to lead Britain, said he would: "Deliver Brexit, unite the country and defeat Jeremy Corbyn," the leader of the opposition Labour party.

"We are going to energise the country. We are going to get Brexit done on October 3 and we are going to take advantage of all the opportunities it will bring in a new spirit of 'can do'," Johnson told party members at the result announcement in London.

However, Johnson has so far not set out anything that would change the British negotiating red lines, which produced the divorce deal, that was agreed by May's government last year, but rejected by the parliament three times.

He has called the Brexit withdrawal agreement, negotiated over a year, "dead", but said he would "take the bits that are serviceable and get them done", such as guaranteeing the rights of 3.2 million EU citizens in the UK.

He said the Irish border can be dealt with after the UK leaves the EU, instead of as part of the withdrawal agreement.

But the EU and Ireland insist that is impossible, as the backstop - coined to keep the border on the island of Ireland open - is an insurance policy that needs to work from the day after Brexit.

Johnson wants to ditch the Irish backstop, which he has called "a prison". He has said there are "abundant, abundant technical fixes" to avoid checks at the border.

The UK and EU negotiators have looked at several options, and none at this point can replace border checks, the EU has argued repeatedly.

The new premier has also previously threatened to withhold the money the UK owes the EU as part of its contribution to the budget until 2021, and has already agreed to pay under the divorce deal.

Johnson hopes to use this as a negotiating tool to get a better deal.

But the EU has said it will not start negotiations on the future trade deal with the UK unless it settles its financial obligation to the bloc.

EU Commission vice president Frans Timmermans warned that the EU will stick to the withdrawal agreement negotiated with the UK.

"He [Johnson] took a long time deciding whether he is for or against Brexit. Now his position is clear, and the EU's position is also clear. UK reached an agreement with the EU and the EU will stick to that agreement," he said.

"We will hear what the new prime minister has to say when he comes to Brussels, but I'm not telling any secrets when I'm saying that Boris Johnson took his time deciding whether he is one side or the other side of the argument, he did that publicly," he said.

"A no-deal Brexit would be a tragedy for all sides. We are all going to suffer if that happens," Timmermans added, saying people did not vote for a no-deal Brexit.

The EU's Brexit negotiator Michel Barnier said he looked forward to" working constructively" with Johnson, "to facilitate the ratification of the withdrawal agreement and achieve an orderly Brexit".

The EU parliament's Brexit coordinator Guy Verhofstadt said that Barnier and the parliament's Brexit group will meet on Wednesday to respond to Johnson's appointment.

Irish deputy prime minister, Simon Coveney said Ireland will work with Johnson constructively to "maintain and strengthen British-Irish relations though the challenges of Brexit".

Salvini happy

Italian populist interior minister Matteo Salvini welcomed Johnson's appointment.

"The fact that on the left they depict him as 'more dangerous than the League' makes me like him even more," Salvini tweeted, who also leads the far-right League party.

Lithuania's EU commissioner Vytenis Andriukaitis warned that Johnson's populism can lead to authoritarianism.

In a blog post he likened Johnson's "unrealistic promises" to those of the former Russian president Boris Yeltsin, which paved the way in the authoritarian rule of Vladimir Putin.