The government is to end an arrangement that allows other countries to fish in UK waters, it has been announced.
The convention allows Irish, Dutch, French, German and Belgian vessels to fish within six and 12 nautical miles of UK coastline.
Environment Secretary Michael Gove said the move would help take back control of fishing access to UK waters.
But Greenpeace said ending the arrangement would not alone improve the future of the UK’s fishing industry.
The London Fisheries Convention sits alongside the EU Common Fisheries Policy, which allows all European countries access between 12 and 200 nautical miles of the UK and sets quotas for how much fish nations can catch.
Withdrawing from the convention, which was signed in 1964 before the UK joined what became the EU, means UK vessels will also lose the right to fish in waters six to 12 nautical miles offshore of the other countries.
Mr Gove said leaving the convention meant “for the first time in more than 50 years we will be able to decide who can access our waters”.
He added: “This is an historic first step towards building a new domestic fishing policy as we leave the European Union – one which leads to a more competitive, profitable and sustainable industry for the whole of the UK.”
The industry body, the National Federation of Fishermen’s Organisations, welcomed the decision.
Chief executive Barrie Deas said: “This is welcome news and an important part of establishing the UK as an independent coastal state with sovereignty over its own exclusive economic zone.”
But Will McCallum, Greenpeace UK head of oceans, said leaving the convention would not in itself deliver a better future for the UK fishing industry, and that for years governments had blamed the EU for their “failure” to support the small-scale, sustainable fishers.
He said Mr Gove needed to keep the 2015 Conservative Party manifesto commitment to “re-balance fishing quotas in favour of small-scale, specific locally based fishing communities”.
Environmental law firm ClientEarth consultant Dr Tom West said the move appeared to be an aggressive negotiating tactic.
“As a country outside the EU we need to consider how we can best co-operate with our neighbours, rather than unilaterally withdrawing from all agreements in the hope that standing alone will make us better.”