They have set a deadline of Friday for the Government to offer a solution to the licences stand-off or start blockades of Calais, Dunkirk and the Channel Tunnel which could throttle the flow of goods across the Channel.
Benoît Firmin, of the Hauts de France fishing committee, stressed that blockades, if they go ahead, are set to be more widespread than previous protests.
On the impact on Christmas supplies, he told the BBC: ”We haven’t even blocked yet and already there’s a lack of food, petrol and staff (in the UK).
“Are we going to make things worse? Maybe, but there’s a lot of frustration among the community, so fair enough.”
Laurent Merlin, whose boat is based at Boulogne-sur-Mer and whose family had until Brexit fished in British waters for 25 years, added that fishermen were waiting until Friday but would then start to retaliate.
“We will create as much disruption as we can by blocking primary goods, the things Britain needs the most,” he warned.
“We saw the gas shortage. We will try to create another shortage of something else.
“We are ready to block everything, Calais, Dunkirk, the Channel Tunnel.”
The threat from French fishermen came as relations between France and Britain have hit a recent low with the fresh Brexit bust-up over the Northern Ireland Protocol and a row over the UK/US deal with Australia on a fleet of nuclear-powered submarines which meant a contract with a French manufacturer of conventionally-powered submarines was ditched.
Shipping and retail bosses in Britain are also already warning that supply chain problems are likely to mean a shortage of some toys and other goods in Britain this Christmas, and advising families not to leave their festive season buying until the last minute.
Rishi Sunak sought to allay worries, insisting there would be a “good amount of Christmas presents available” this year despite the transport issues.
The Chancellor on Wednesday met fellow finance ministers from the G7 group of leading world economies, the US, UK, Germany, France, Italy, Japan and Canada, and they agreed to work more closely to solve the supply chain crisis.
Speaking to the BBC in Washington DC, the Chancellor said: “We’re doing absolutely everything we can to mitigate some of these challenges.
“They are global in nature so we can’t fix every single problem but I feel confident there will be good provision of goods for everybody.
“I’m confident there will be a good amount of Christmas presents available for everyone to buy.”
Retailers have expressed fears ongoing supply chain problems will result in higher prices and empty shelves into December, but the chief executive of the UK Major Ports Group said supply chains were “robust” and “there’s no need to panic”.
A build-up of cargo in Felixstowe has led to shipping company Maersk opting to divert vessels away from the Suffolk port, while similar logjams have been seen elsewhere in the world including in the US.
Mr Sunak chaired a meeting of finance ministers on Wednesday as the International Monetary Fund and World Bank convene in the US capital.
The Treasury said Mr Sunak told the meeting of the “importance of global co-operation to ensure that supply chains are more resilient as the world emerges from the pandemic”.
Speaking after the meeting, the Chancellor said: “Supply chain issues are being felt globally – and finance leaders from around the globe must collaborate to address our shared challenges.
“Today we have collectively agreed to work closely over the coming months – and together we will build a strong and resilient recovery.”
However, many households in the UK face a winter cost-of-living crisis with soaring energy bills, higher inflation, the axing of the £20 pandemic uplift in Universal Credit, and looming National Insurance rises in the spring.