Dr Marcus Papadopoulos, who runs PoliticsFirst, said that a post-Brexit Britain will become "pointless" in the world.
Contrary to hopes of a global, outward-looking Britain, the diplomatic expert warned that Brexit could see the country case adrift.
In an interview with Bloomberg Asset TV, Dr Papadopoulos warned that the EU are already persuading major companies to move factories from the UK to Europe.
This comes as Angela Merkel met both Indian and Chinese diplomats in the past week to push for EU trade deals with the two growing economies.
The German leader's economic drive flies in the face of the UK's hopes to strike free trade deals with those very economies.
The EU are already persuading major companies to move factories from the UK to Europe
One of the key pledges of Brexit was the chance to strike free trade deals across the world
Dr Papadopoulos said that the EU had beat the UK to the punch on free trade, and warned about Brexit's impending losses.
He told Bloomberg report Jenny Hammond: "People vote on the economy and this election is the Brexit election.
"But the economists I talk to say that Theresa May's slogan of 'no deal is better than a bad deal' is wrong – a no deal Brexit is the worst of the lot."
The TV commentator added: "British businesses are scared. Many businesses find the fact that Britain won’t have access tot he single market concerning.
"I speak to Chinese, Indian, Japanese diplomats and they are alarmed because for decades Britain has been the bridge to Europe – a bridge to re-export goods to mainland Europe.
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"If that bridge is not there, they tell me – what is the point of Britain?
"They will just move their factories to mainland Europe and not have to pay import tariffs. This will have a massive impact."
Factories run by Chinese and Indian companies should move from the UK to Europe
Dr Papadopoulos said that the EU had beat the UK to the punch on free trade
If that bridge is not there, they tell me – what is the point of Britain?
Dr Marcus Papadopoulos
The European Union move towards a massive free trade deal with India, announced this week, will shock Brexiteers.
One of the key pledges of Brexit was the chance to strike free trade deals across the world – however, the German Chancellor apepars to have beaten the UK to this on Tuesday.
According to German analysts, Brexit will actually make free trade deals easier for the EU, as Britain was often thought to have held up talks over concerns about visas to Indian workers and tariffs on whisky.