Defra is to get its own squadron of armed patrol boats to prevent European boats fishing illegally in UK waters.
The first ship of four, HMS Forth will have a 30mm gun, machine guns and a helicopter when it enters service next year.
The others will be built at a cost of £350million, and one is being sent to the Falklands.
The navy ships will be paid for by the Marine Management Organisation, part of the Department for Environment, Food and Rural Affairs, to patrol coastal waters in a contract worth millions of pounds.
The ships form part of a policy to strengthen policing of UK waters once we leave the bloc in March 2019.
A Defra spokesman said: “Leaving the EU means we will take back control of our waters. Access will be subject to negotiation, and will support a thriving future for our fishing sector.
“We are reviewing all aspects of fishery management, including satellites, patrol vessels and aerial surveillance.”
The news comes after Admiral Lord West said Britain’s three vessels were too few and the UK would be a “laughing stock” if it was unable to police the coastal waters.
Having just three ageing vessels meant often there were just one or two on patrol covering the 80,000 square miles of territorial waters.
Lord West said: “As we leave the EU we will have to review and reflect on the level of fisheries enforcement required.”
British waters currently provide around a third of the EU’s catch and Danish, French and Spanish fishing vessel operators have all said they will challenge any attempt to keep them out of UK waters.
The French have even threatened to blockade the Channel ports in retaliation.
Jim Portus, chief executive of the South West Fish Producer Organisation, welcomed the new vessels and told the Sunday Times deployment would have to be intelligence-led.
He said: ”Yes, there are risks of port blockades, especially by the French. They do it so often. But we already have technology like satellites, plus CCTV cameras on many vessels. There will be 1,000 UK fishing vessels just itching to report any illegal activity.”