The Confederation of British Industry (CBI) has warned that 24 of 27 areas of the UK economy face disruption in the event of a no-deal Brexit.
It issued the warning in a report, which also contained 200 recommendations to advise what measures businesses can take to mitigate the worst effects.
The ‘What happens next?' report compiled thousands of interviews with businesses of all sizes and sectors across the whole of the UK economy.
Companies in sectors like financial services, broadcasting and life sciences are best prepared for the immediate impact of no-deal, the CBI said.
It urges firms in all other sectors to resume no-deal preparations immediately in the event the UK fails to strike a deal with the EU.
The UK remains on course to leave the EU on 31 October 2019, with new Prime Minister Boris Johnson claiming in The Times that "no-deal is a very real prospect".
Authors of the CBI report said:
"Much of the business community will not be ready for no-deal.
"For hundreds of thousands of small companies, diverting precious resources - both human and financial - to Brexit preparedness measures is out of reach.
"The change in the scheduled date for no-deal has also had an impact on business readiness."
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