Britain has now made £6.3 billion available to prepare for Brexit.

Britain will provide an extra £2.1 billion ($2.6 billion, 2.3 billion euros) to prepare for leaving the European Union, with or without a deal, doubling its current 2019 budget, the government announced Wednesday.

Finance minister Sajid Javid will immediately release £1.1 billion to "prepare critical areas" for departing the bloc on October 31 with a further £1 billion available "should it be needed", his department said in a statement.

The extra cash will be used to launch a public information campaign and "accelerate preparations at the border, support business readiness and ensure the supply of critical medicines," it added.

New Prime Minister Boris Johnson has vowed to take Britain out of the EU on October 31, even if it means leaving without a deal, despite warnings that it could trigger economic chaos.

Britain has now made £6.3 billion available to prepare for Brexit, including £4.2 billion for 2019, after previous finance minster Philip Hammond made £2.1 billion available in his budget last October.

"With 92 days until the UK leaves the European Union it's vital that we intensify our planning to ensure we are ready," said Javid.

"If we can't get a good deal, we'll have to leave without one. This additional £2.1 billion will ensure we are ready to leave on 31 October - deal or no deal," he added.

The £344 million targeted for border and customs operations will help fund an 500 extra border force officers and improve transport infrastructure around ports.

Another £434 million will be made available to help ensure the supply of medicines and medical products while £108 million will help businesses prepare for the fall out.

An information campaign aimed at the general public will also receive £138 million.

Britain was due to leave the EU on March 29, but MPs rejected then prime minister Theresa May's deal struck with Brussels three times, forcing her to ask for an extension.

Johnson, a leading Brexit campaigner, came to power last week pledging Britain will leave on the new deadline of October 31, but MPs could try and force him into an election in an effort to prevent a no-deal Brexit.