British Prime Minister Boris Johnson is preparing to impose full customs and border checks on all European Union goods entering Britain from next year, in an attempt to increase pressure on the bloc in trade talks, The Daily Telegraph newspaper has reported.

"We are planning full checks on all EU imports - export declarations, security declarations, animal health checks and all supermarket goods to pass through Border Inspections Posts," this morning's Telegraph quoted a senior government source as saying.

"This will double the practical challenge at the border in January 2021," the source added.

Under previous government plans for a no-deal Brexit last year, where Britain left the EU abruptly without any trade deal, only a small proportion of goods would have been checked.

Britain left the EU at 11pm with a temporary transition deal, starting an 11-month period during which Mr Johnson aims to negotiate a free-trade agreement similar to that between Canada and the EU.

British negotiators hope that threats of tougher checks if a deal is not agreed could make the EU more willing to agree to Britain's terms, the Telegraph said.

Without a deal, British goods exports will face EU tariffs from next year. Even with a deal, extra checks are likely on both sides of the border, prompting the Bank of England to warn last week of damage to trade and economic growth from next year.

The intensity of these checks will affect costs for British businesses that rely on just-in-time delivery, such as carmakers and supermarkets, and some fear even small border delays could make them uncompetitive, or reduce choice for shoppers.

Asked about the Telegraph report, a spokeswoman for Mr Johnson's office said change was inevitable.

"We are leaving the EU's customs union and single market.That means businesses will have to prepare for life outside of these," she said.

The British Chambers of Commerce (BCC) said the government should prioritise a continued free flow of goods through ports after the transition period ends.

"Costs add up with every new procedure or delay - and every pound spent on adapting to new requirements is a pound less for training, equipment or securing new customers," BCC director-general Adam Marshall said.