Johnson, who took office last week, wants to change the exit terms struck by predecessor Theresa May but insists he will leave the European Union without any agreement at all if necessary on October 31.

Brussels has said it will not reopen the text.

"The withdrawal agreement is dead," Johnson told reporters during his first visit to Scotland.

"I am confident we will get a deal but it is also right we prepare for no deal," he said.

The government has not yet announced plans for Johnson to visit EU capitals, and a spokeswoman indicated he would not go until Brussels changes its stance.

"He obviously wants to meet EU leaders and negotiate but not to be sat down and told that the EU cannot possibly reopen the withdrawal agreement," the spokeswoman said.

The Confederation for British Industry (CBI), the country's top business lobby group, said companies now needed to be on an "emergency footing" because of the growing likelihood of no deal.

The pound lost more than one percent of its value against the dollar on Monday, hitting a two-year low.

In a report, the CBI warned that both Britain and the EU were not prepared for a no-deal Brexit and urged businesses to step up contingency plans.

The group's head of EU negotiations Nicole Sykes tweeted that it was "like putting sandbags down for a flood".

"Your kitchen's still going to be underwater but MAYBE we can save the bedroom upstairs," she wrote.