Britain's exit from the European Union has so far made trade more expensive because of delays and red tape, and there could be border disruption as passenger numbers recover after the Covid pandemic, the UK Public Accounts Committee said today.

Supporters of Brexit said exiting would allow the UK the independence to escape what they cast as a stagnating German-dominated project that was falling far behind big powers such as the US and China.

But opponents of Brexit cautioned that leaving the EU was akin to an act of self harm that would leave the UK diminished, poorer and more insular.

While trade was suppressed by the Covid-19 pandemic and other global supply constraints, the UK parliament's Public Accounts Committee found that the "EU exit has had an impact, and that new border arrangements have added costs to business".

"One of the great promises of Brexit was freeing British businesses to give them the headroom to maximise their productivity and contribution to the economy," said Meg Hillier, chair of the committee.

"Yet the only detectable impact so far is increased costs, paperwork and border delays," she added.

The leaders of Brexit said that in the short term there could be additional costs as the UK adapted, but that in the long term there would be considerable political and economic benefits from leaving the bloc.

The Public Accounts Committee cautioned that the UK government had considerable work to do to make cross-border trade easier for businesses and that there were concerns about computer systems being developed by customs.

In November, Britain became the last Group of Seven developed nation to see its goods exports surpass their 2018 average level since the onset of the Covid-19, underlining its poor trade performance in international terms.