Britain is recalling two patrol boats from overseas deployment to help deal with an increase in the number of migrants trying to reach the country from France, interior minister Sajid Javid said on Monday.
Mr Javid said there had been an increase in the number of migrants crossing the English Channel from France and last week he declared the situation a "major incident".
On Monday, following a meeting of officials in London, he said the two additional ships would join three other vessels working in the channel.
He said 230 migrants had attempted to cross one of the world's busiest shipping lanes in December, although almost half were prevented from leaving France.
The number is a tiny fraction of those regularly attempting to reach European Union territory by crossing the Mediterranean from northern Africa and Turkey, many of whom are fleeing conflict and poverty in Middle East and Africa.
But, their attempts have attracted extensive domestic scrutiny in Britain amid a febrile political atmosphere surrounding Brexit in which immigration was a major theme.
"This will help both with the human side of this situation but also to better protect our borders," Mr Javid said of the deployment.
The last three months accounted for around 80 per cent of all attempts in 2018, Mr Javid said, adding crossings were up in 2018 compared to 2017.
The interior ministry said the majority of those who had arrived in Britain in the recent period were Iranian but said it did not routinely publish data and would not be providing a running tally or exact comparisons with previous years.
Local media reported that 12 people arrived at a beach in southeast England by small boat on Monday.
Mr Javid cut short a holiday to oversee response to the situation and is seen as one of those jostling to replace Prime Minister Theresa May after she said earlier this month she would step down before the next scheduled nation election in 2022.
Concern over both legal migration and illegal immigration was seen as an important driver of the 2016 vote to leave the European Union.
"I don't want people to think that if they leave a safe country like France, that they can get to Britain and just get to stay," Mr Javid said, outlining a desire to work with France to return as many of the migrants as possible.