And he suggested the hustle and bustle of the centre of the EU‘s political machinery – and the vast number of visitors coming and going daily – offered the perfect environment for coronavirus to spread. Meanwhile Dr Bull also said his experience of being ill – as well as the circumstances in which he feels he contracted the illness – have underlined for him both the importance of social distancing, and the difficulty of being unable to tell who had had it and who had not. Dr Bull, former Brexit Party MEP for South East England, told Express.co.uk: “We’ve never seen this before.

“I think it’s fairly clear is that virus was around a lot earlier than I think.

“And also, if you look at places like the European Parliament, it is a meeting place. There were definitely people from China there because they were lobbying.

“I know a number of Chinese companies were there at that time.

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“And of course, you have all of those parliamentarians and the staff going back to their home countries.”

Describing his own experience, which prompted him to self-isolate, he said: “I started to feel really ill after we had left. In February I was really ill.

“And then I was ill again in March, two weeks ago.

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“But I think the thing is that essentially the study that came out of Imperial College, frightened the Government.

“The herd immunity, which was the initial idea, may well have worked.

“But they were then saying, if you don’t do anything, you’re going to end up with 500 to 800,000 deaths, which would obviously be completely unacceptable for many reasons.”

As for the great unknown – the number of people who have already had COVID-19 and therefore likely to have at least some resistance – Dr Bull added: “The Prime Minister is in a very difficult situation, because we don’t have hard data.

“What we do know the only hard data we have is fatality.

“How many people have died is only thing we know for sure right now.”

Dr Bull also said he had also been struck by the community spirit being demonstrated by Britons in a time of adversity.

He explained: “The reaction we are seeing has been amazing.

“The community spirit people are showing, coming forward to deliver food and drop it outside older people’s homes and all the rest of it, is wonderful.”

A spokesman for former Brexit Party leader Nigel Farage was adamant Mr Farage had not had the virus, having displayed no symptoms.

However, he told Express.co.uk in common with the vast majority of the UK population, the long-term anti-EU campaigner had not been tested.