Britain's Prime Minister Boris Johnson and Scottish First Minister Nicola Sturgeon. Picture: Duncan McGlynn/Pool via Reuters.

London - British Prime Minister Boris Johnson met Scottish First Minister Nicola Sturgeon as he took his Brexit campaign to Scotland on Monday, but he was criticised for failing to contact his Irish counterpart.

Johnson visited a submarine base in Scotland ahead of his talks with Sturgeon, who has warned that the appointment of Johnson to succeed Theresa May as Conservative prime minister makes holding a referendum on Scottish independence "more important than ever"

"As we prepare for our bright future after Brexit, it's vital we renew the ties binding our United Kingdom," Johnson said ahead of of the talks, promising an extra 300 million pounds (372 million dollars) to support growth in Scotland, Wales and Northern Ireland.

Johnson said he also plans to visit Northern Ireland to discuss the restoration of the territory's devolved power-sharing government, which has been suspended since January 2017.

Michelle O'Neill, Irish republican party Sinn Fein's leader in Northern Ireland, accused him of a "highly offensive" snub of Irish Prime Minister Leo Varadkar, after Johnson apparently failed to contact him since he took office on Wednesday.

O'Neill said she raised Johnson's failure to call Varadkar with Britain's new Northern Ireland Secretary Julian Smith in Belfast on Monday.

"That is highly offensive given the disastrous impact of Brexit on the island of Ireland," she said.

Johnson has spoken to other leaders by phone since taking office, including US President Donald Trump, French President Emmanuel Macron, German Chancellor Angela Merkel and the European Commission president Jean-Claude Juncker.

The Daily Telegraph reported earlier Monday that he will launch the biggest British government propaganda campaign since World War II in a bid to rally the public behind his Brexit plan.

Johnson's Conservative government will spend some 100 million pounds (123 million dollars) on advertising over the next three months as a major part of the campaign, the newspaper quoted unidentified government sources as saying.

It said the drive will be "the biggest advertising campaign since the Second World War to get Britain ready for a no-deal Brexit, with an unprecedented marketing blitz on billboards, radio and television."."

Johnson has vowed to withdraw Britain from the EU by the delayed exit date of October 31, with or without a deal.

His government is "operating on the assumption" that Britain will leave without a deal, Cabinet Office minister Michael Gove wrote in The Sunday Times.

Gove, who is in leading the no-deal preparations, said "the entire machinery of government will work flat-out" to prepare for a no-deal Brexit.

The preparations for leaving the EU without a deal prompted a flurry of new warnings about the potential economic effects on Monday.

The Confederation of British Industry (CBI), which represents some 190,000 businesses, said its analysis of British and EU preparations suggested that "no one is ready for no deal."

"We can reduce but not remove the damage of no deal," said Josh Hardie, the CBI's deputy director-general.

"It's not just about queues at ports; the invisible impact of severing services trade overnight would harm firms across the country," Hardie said.

DPA