Boris Johnson’s claim to have defeated threat of wide-ranging EU tariffs if UK breaches fishing deal rubbished by experts

Boris Johnson’s claim to have fought off the threat of wide-ranging EU tariffs if the UK tries to grab control of more fish stocks has been rubbished by a new analysis.

Brussels has secured the power to inflict sanctions in numerous other sectors – including other goods, services, transport, intellectual property and energy – the Institute for Government (IfG) said.

Its study also disputes a second “win” claimed by Downing Street, to have secured independent arbitration before any punishments can be imposed for alleged breaches of the deal.

In fact, the 1,255-page text says “temporary” sanctions can be imposed in many areas – not only fish, but subsidy controls, regulatory cooperation, law enforcement coordination and the return of cultural property – where tribunals are specifically barred.

The verdict comes as the European Research Group (ERG) of hard Brexit-backing Conservative MPs examines the document, before deciding whether to vote against the deal on Wednesday.

The prime minister has assured the group that there are no nasty surprises that would fail the tests set by its self-styled “star chamber” of lawyers.

On Saturday, a senior member of the UK negotiating team insisted breaches of the fisheries deal could not trigger sanctions on wider trade, saying: “There can be tariffs on fish and that is it.”

The controversy could be crucial because the government has been accused of “betraying” the fishing industry by failing to gain control of stocks in British waters, as promised.

The UK conceded to the EU’s demand to give up only 25 per cent of its catch, at the end of a five-and-a-half-year transition – setting the scene for a future bitter dispute.

The IfG analysis explains the “arrangements for compensation” if the EU or UK breaks the agreement in future.

“This could include suspending or limiting access to waters and ending the preferential tariffs on fishery products or other goods on each other’s market,” it states.

Maddy Thimont Jack, the IfG’s associate director, told The Independent: “They could suspend preferential treatment of any other goods where preferential tariffs apply.

“The first step would be retaliation on fishery products, then retaliation more broadly. This is explicitly not what the UK wanted. But it is also reciprocal – and there are arrangements to try to avoid this happening.”

Downing Street has also claimed success by requiring disputes to be settled by arbitration, probably by panels of foreign judges, arguing the EU wanted to deploy “lightning tariffs”.

But the IfG examination of the text has concluded the UK and the EU “cannot refer disputes” in many areas “to the independent tribunal”.

“Instead, the UK and the EU Commission can use temporary trade remedies or rebalancing measures,” it states.

Ms Thimont Jack said the UK had secured a “key win” by shutting the European Court of Justice out of dispute resolution. It will have authority over the separate Northern Ireland Protocol.