Leave Means Leave co-chairman Mr Longworth blamed pro-EU associations such as the Confederation of British Industry (CBI) for the compromises the British Government has had to make so far with the European Union.
The economist believes that agreeing to stay under the EU rules for 21 more months during the transition period equals to becoming a “vassal state of the EU”.
In an op-ed published by The Times he wrote: “For the privilege of having no say in EU affairs but being a rule taker, the UK taxpayer will hand over to the EU the equivalent of our Second World War debt. You could not make it up!
“During this period our fishing grounds will continue to be plundered and quotas stitched up in favour of the Continent and the prime minister will have signed up to a ‘backstop’ deal on Northern Ireland, which is the antithesis of her categoric statement that no British prime minister would countenance the annexation of British territory by a foreign power.”
The way out for Mr Longworth would be to accept a “perfectly satisfactory” Canada-style deal, which the EU has repeatedly said is ready to agree to, and walk away from the EU in March 2019.
Although “it won’t cover the 0.75 per cent of GDP from financial services for which there is a single market”, this deal could cover “at least 98 percent of goods and 92 percent of agriculture”.
The EU-Canada Comprehensive Economic Trade Agreement (CETA) has been lauded as “the gold standard for future deals” by both the EU and Canada.
It abolishes almost all tariffs on goods and reduces some non-tariffs barriers, promising greater cooperation between the two blocs.
It also offers improved access to some services markets, like telecoms, energy and maritime transport, and allows firms to bid for public procurement contracts in the others.
The Government, Mr Longworth believes, made the mistake of not declaring from the very beginning of the negotiations its vision for the post-Brexit economy.
Stating clearly which financial goals the UK wanted to achieve with Brexit would have both reassured Remain-backing organisation and “invited the EU to discuss a trade arrangement if they wished to”.
Mr Longworth wrote: “Of course ‘no trade, no money’ would have been our mantra.
“It would have provided certainty, thus no so-called cliff edge and no need for a transition.
“As it is we now have another cliff edge in 2020.”
Showing little to no trust in the desire of EU negotiators or “our flaky civil servants” to solve any other issue besides the one concerning the Irish border during the transition period, Mr Longworth urged the Government to stop delaying all manifest opportunities and benefits of Brexit and seize them in March 2019.