A no-deal Brexit could cost the UK economy £50bn, according to independent economic analysis commissioned by Mayor of London Sadiq Khan.
The report models five possible scenarios for leaving the EU, warning the worst option could result in a “lost decade” for the British economy.
“There is no sector not negatively impacted,” Mr Khan told BBC Radio 4’s Today programme.
The analysis by Cambridge Econometrics predicted a no-deal agreement could also cost up to half a million jobs, with as many as 87,000 disappearing from London alone.
Even with a two-year transition period, moving on to World Trade Organisation rules could mean as many as 470,000 fewer jobs, the report says.
Mr Khan said: “This independent analysis reveals the potential economic risks – and human costs – at stake in the negotiations.
“If the Government continues to mishandle the negotiations we could be heading for a lost decade of lower growth and lower employment.
“The analysis concludes that the harder the Brexit we end up with, the bigger the potential impact on jobs, growth and living standards.
“Ministers are fast running out of time to turn the negotiations around.
“A no-deal hard Brexit is still a very real risk – the worst possible scenario.
“I’ve released these impact assessments because the British people and our businesses have a right to know the likely impact of the various options the Government are considering on their lives and personal finances.
“This new analysis shows why the Government should now change its approach and negotiate a deal that enables us to remain in both the single market and the customs union.
“It’s astonishing that the Government has failed to do any proper impact assessments on what Brexit could mean for our economy.
“Their complete lack of preparation is irresponsible, leading to fears that they are putting party politics ahead of the national interest.”
Conservative London Assembly member Gareth Bacon accused Mr Khan, a “well-known Remainer” and “advocate of Project Fear”, of a “continuation of his widely-publicised anti-Brexit views”.
“This is hardly a surprise, particularly given that most of the authors of this ‘independent’ report are already on record as vehemently opposing Brexit,” he said.
“The fact is, the economic collapse that Remainers like Sadiq Khan predicted would happen immediately after the referendum, has not occurred.
“The Government and the European Union are engaged in long and complicated negotiations, and, until the outcome is known, this is merely scaremongering and speculation.”
Additional reporting by PA
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