Many U.K. small companies are facing an “existential” threat as they grapple with obstacles Brexit has imposed on trade with the European Union, one of the country’s largest business groups said.

About half of U.K. exporters are experiencing difficulties, mainly in the form of extra documentation, higher costs, and delays to shipments, according to a survey of 465 firms by the British Chambers of Commerce. About 95% of the respondents were small businesses.

Since Britain left the EU’s single market and customs union on Jan. 1, companies have had to adapt to a raft of new paperwork when sending goods to the EU, the U.K.’s biggest and closest trading partner.

Agricultural exports—in particular food and meat—have been particularly badly hit by the need to provide export health certificates signed by a qualified vet, leaving trucks that once moved freely across the Channel facing days-long delays at times.

‘Hit Hard’

Companies “are being hit hard by changes at the border,” said Adam Marshall, director-general of the BCC. “For some firms, these concerns are existential.”

Businesses are also bracing for extra controls which will apply to imports from the EU from April and July, threatening to coincide with rising economic activity as the U.K. emerges from lockdown restrictions. Marshall said the government should postpone these controls, and significantly increase the support it offers to companies.

“This situation could get worse,” he said. “These timescales need to change.”

The Brexit changes have also coincided with difficulties caused by the coronavirus pandemic, Hannah Essex, the BCC’s co-executive director, told Bloomberg TV.

“Cash flow is a real challenge for many people,” Essex said. “Shipping is also a challenge that’s been compounded by the pandemic.”