Progress in passing a bill to stop a no-deal Brexit in parliament has been a “chink of light” for UK business, according to the head of Confederation of British Industry (CBI).
However, Carolyn Fairbairn told the BBC the “cloud has not gone away” for companies until a deal is agreed.
She said many would have to keep stockpiling, even though the bill is likely to be ready for royal assent on Monday.
“The clock is still ticking,” she said.
On Thursday, the government confirmed the bill – designed to force the prime minister to seek an extension to the 31 October Brexit deadline – would complete its passage through the Lords on Friday.
The proposed legislation was passed by MPs on Wednesday, inflicting a defeat on Prime Minister Boris Johnson.
However, the government – which wants the UK to leave the EU on 31 October with or without a deal – is seeking support for an election on 15 October.
As a result, Ms Fairbairn said, many business would continue to prepare for a potential no-deal.
“So many businesses are stockpiling for 31 October in the same way they did for 29 March at enormous cost and expense,” she said.
“It’s so wasteful and I think they will have to continue to do that until they know otherwise.
“And I think more and more are deeply concerned about the long-term effect on their competitiveness; they are seeing a loss of market share internationally that is very hard to claw back.”