Ageing Border Force vessels will be replaced by new cutters as part of a £700 million investment to improve the safety of Britain’s borders, the Treasury said.

The current fleet, which is 20 years old, will be retired and 11 new vessels will come into service to help tackle organised crime and illegal migration at a cost of £74 million.

The announcement was made ahead of Chancellor Rishi Sunak’s budget and also includes £628 million “to modernise and digitalise the border”, with proposals including a US-style Electronic Travel Authorisation for tourists wishing to come to the UK.

Protecting our borders and making it easier for us all to travel to and from our great nation is at the heart of our ambitions as a government

Electronic authorisations will launch in 2023 and be fully in place two years later and, like the American system, will allow authorities to decide if people should be allowed to travel to the UK prior to their arrival.

In a statement issued by the Treasury, Mr Sunak said: “Protecting our borders and making it easier for us all to travel to and from our great nation is at the heart of our ambitions as a government.”

It comes just over a month since figures, compiled by the PA news agency, showed the number of people who have made the dangerous journey across the English Channel in small boats this year has doubled the total for all of 2020.

Since the start of the year, more than 18,000 people have succeeded in reaching the UK on board small boats, according to data.

Small boat arrivals in 2021 now stand at more than double the figure for the whole of 2020, when 8,417 people crossed the Dover Strait.

The Spending Review will also include just over £1 billion to be spent over the next three years on “new UK sovereign functions” following Brexit.

This will include money for more than 1,000 Border Force officers to deliver customs and transit checks, the Treasury added.