Visitor numbers a tiny fraction of the 66m target as National Audit Office launches inquiry.

The government's so-called "Festival of Brexit" is to be investigated by the public spending watchdog after it was reported the £120m project attracted less than 1% of its targeted visitors.

U.K. investment of more than 1 billion pounds ($1.4 billion) to smooth the passage of goods over its new post-Brexit border failed to prevent a slump in trade with the European Union.

Exporters forced to fill in 48 million customs declarations and 140,000 health certificates over eight-month period.