Ben Habib, a former Brexit Party MEP, made the claim in response to a French threat to cut power to Jersey over a fishing row. France claims some of its fishing vessels have been denied access to UK waters by overly complicated bureaucracy.
They are also angered by restrictions imposed by Jersey, a self-governing British Crown Dependency.
In response French maritime affairs minister Annick Girardin warned her country could use “the transmission of electricity by underwater cable” as leverage.
Around 95 percent of the electricity used by Jersey is imported from France.
Writing for the Daily Telegraph Mr Habib argued the EU is attempting to maintain control over the UK despite Brexit.
He said: “No one should be surprised that France is prepared to switch off the lights in Jersey to get our fish.
“The Withdrawal and Trade & Cooperation agreements do not herald the beginning of a harmonious future trading relationship.
“They are the instruments by which the EU will keep us at its heel and roundly punish us should we try to slip the leash.”
Whilst Britain formally left the EU in January 2020 it remained closely tied to the bloc, via the Brexit transition period, until the following December.
READ MORE: UK backs down – Brexit Britain recognises EU ambassador
“It is a fallacy that there is a transition period ending in 2025, after which full control comes back to the UK.
“The only way to regain control of our waters is if we are prepared, again, to suffer sanctions or terminate the trade deal itself.”
Mr Habib was also fiercely critical of the EU’s conduct over Northern Ireland.
Under the terms of Mr Johnson’s trade deal some regulatory checks are being imposed between Northern Ireland and the rest of the UK.
This has infuriated unionists who fear it undermines their place in the UK.
Serious loyalist rioting across the province last month was partly attributed to this anger.
In his article Mr Habib accused the EU of enforcing the Northern Ireland protocol “to the hilt, caring not one jot for its people”.
He added: “It even invoked Article 16 of that Protocol, albeit briefly, in an attempt to prevent lifesaving vaccines from reaching the UK.
“To add insult to injury it is taking the UK to court over our unilaterally extending grace periods to allow goods from Great Britain to cross the Irish Sea.
“Yes, the UK is being sued by a foreign power simply because it wishes to access another part of its own country.”