The Navy could be called in to help reduce the number of illegal migrants crossing the Channel after 235 reached the UK in a new record for a single day.
Priti Patel, the Home Secretary, has ordered a review of the UK's current sea capability in the Channel, which could see the Navy recalled to help tackle the situation for the first time since her predecessor, Sajid Javid, requested military aid last January.
"We are looking at what other assets might be needed – including, potentially, the Navy," said a Government source. "We would need to decide their exact role, but we don't want them to become a taxi service."
Around 1,100 migrants arrived in the UK during July, with the total since the start of the year having risen to around 3,800 – more than double the 1,850 who made the crossing in 2019.
Tobias Ellwood, the Conservative chairman of the Commons defence committee, said: "The Navy's fleet is a national asset and, if there is a spike in the Channel, then a supportive arrangement from the MoD to the Home Office should be triggered in order to protect our shores."
Last January, offshore patrol vessel HMS Mersey was deployed at a cost of £20,000 a day to support Border Force cutters, with other Navy boats recalled from the Mediterranean to offer further backing.
Ms Patel was due to hold crisis telephone talks with her French counterpart, interior minister Gerald Darmanin, on Thursday night "because clearly more needs to be done to stop the boats leaving France". She has also held "gold" level calls with Border Force officials.
The Home Office has chartered a plane to return a "small number" of migrants to France next week after deciding their claims for asylum should not be pursued in the UK but, under EU rules, in the first country in which they arrived. That is likely to provoke a court battle with asylum lawyers.
Last month, Ms Patel criticised her French counterparts for failing to stop migrants at sea and return them to France, saying there could be "stronger enforcement measures on the French side".
The Home Secretary is seeking a new agreement with France under which any migrants picked up anywhere in the Channel or on land should be returned to France as the only way to deter more people from making the perilous journey.
Thursday's migrant arrivals surpassed the previous record of 202 on a single day last month. More than 120 men, women and children, including one baby, were reportedly seen being taken aboard rescue vessels.
One boat reached Dungeness, in Kent, where one witness described seeing what appeared to be three family groups, along with two men on their own, sitting or lying exhausted on the beachfront.
The Home Affairs Committee, led by the Labour MP Yvette Cooper, announced that it would be carrying out an inquiry into the surge in migrants. It expressed alarm at the jump in the number of crossings compared with the fewer than 500 people detected entering the UK by boat in 2018.
The inquiry will examine the role of both the UK and French authorities, including how they are combating illegal migration and supporting legal routes to asylum.
A committee statement on Thursday said: "The committee will also investigate the conditions experienced by people gathered in northern France seeking to enter the UK. This will include the risk to life when attempting to cross the Channel, the world's busiest waterway, in small boats, and the response of UK authorities when they reach the UK, in particular unaccompanied children."
It will also examine "future arrangements for safe, legal routes for family reunion" and those claiming asylum in the UK.
In recent weeks, the Home Office has hit out at "inflexible and rigid" asylum regulations that it says are "not fit for purpose". Ms Patel's department criticised the Dublin Regulation, which determines which EU member state is responsible for examining an asylum application.
It added that, at the end of this year, the UK will no longer be bound by EU laws and can negotiate its own returns agreement.