The UK economy could swell by £135bn a year, according to pro-Brexit economists, if trade tariffs and barriers are removed. The Economists for Free Trade believe a hard Brexit would be best for the UK as it would encourage productivity and force members of the European Union to sign free-trade deals.

"Hard Brexit is good for the UK economically while soft Brexit leaves us as badly off as before... hard is economically much superior to soft," said Professor Patrick Minford, professor of economics at Cardiff University.

More from IBTimes UK

"Backers of soft Brexit say it would preserve jobs, but what they really mean is that it would preserve existing jobs by stopping competition from home and abroad. As every schoolboy knows and every politician ought to know, this aborting of competition reduces jobs in the long run.

Eliminating trade barriers, he claims, would add at least £80bn and deregulating the economy another £40bn. In total, the group believes £135bn would be added. If realised, the government could in a single year pay for:

  • a second Heathrow runway (£18bn);
  • HS2 rail project (£56bn);
  • London's Crossrail (£15bn);
  • Hinkley Point nuclear power station (£20bn);
  • Westminster Palace renovation (£4bn); and
  • more than 30 state-of-the-art hospitals - according to figures from Brexit-supporting MEP Daniel Hannan.

The plan was dismissed by pro-soft Brexit group Open Britain, whose supporter Labour MP Alison McGovern, said scrapping tariffs without achieving similar reductions in the tariff rates of other countries would see Britain "swamped with imports, leaving our manufacturers and farmers unable to compete."

She added the project is one of "economic suicide, not prosperity".