Once that is received, there will be a two-year negotiating process before the UK finally breaks away in 2019.

In response to the news, EU president Donald Tusk said he would have draft negotiating guidelines ready within 48 hours of receiving the letter. The remaining 27 EU member states are expected to meet during May to draw up their negotiating stance.

Margaritis Schinas, the European Commission’s chief spokesman, said: “We are ready to begin negotiations. Everything is ready on this side.”

The start of negotiations will come nine months after the UK voted to leave the EU by a 52% - 48% majority in a referendum on June 23 last year.

The UK’s Brexit secretary David Davis said: “We are on the threshold of the most important negotiation for this country for a generation.

“The Government is clear in its aims: a deal that works for every nation and region of the UK and indeed for all of Europe - a new, positive partnership between the UK and our friends and allies in the European Union.”

Priti Patel, the UK’s international development secretary, said: “What this shows is that we are a government that is very focused. We have a plan for Britain and we also have a very clear plan for Brexit. We will get on and make sure that Brexit works for everyone in the UK.”

The notification marks the first time the Article 50 provisions, which outline the process for any EU member state to pull out of the union, have been activated.

The move will also come just days after European leaders gather in Italy to mark the 60th anniversary of the Treaty of Rome, which laid the foundations for the EU. 

A critical element of the negotiations will be trade agreements between the UK and the rest of the EU, with business leaders throughout Europe fearing that the return of tariffs will damage growth and cost jobs.

Last month, the UK finance and leasing industry was warned about the difficulties it will face in the coming years.

Former UK chancellor Alistair Darling told 1,500 senior figures attending the Finance and Leasing Association annual dinner in London last month that the country and the industry faced a difficult future.

Lord Darling, now a member of the House of Lords, said: “We as a nation have bought a ticket to a very uncertain destination.

“I have never heard of a negotiation where you get everything you want. Whatever we get will not be as good as what we have at the moment.

“There is a substantial chance there will be a car crash in two years’ time. Don’t underestimate the difficulties you will face. It will be a long and tortuous process.”

However, new research from Hitachi Capital British Business Barometer shows that small to medium-sized businesses in the UK manufacturing sector are increasingly optimistic about their fortunes outside the EU.

Nearly half (49%) anticipate growth in the next three months, up from 31% six months ago. The percentage of SMEs anticipating decline is down from 12% to 9%, suggesting improved levels of confidence within the sector.