The majority of British adults think Boris Johnson’s bridge proposals are ‘vanity projects’ and prefer investment into underground systems in major cities.

The former foreign secretary has proposed a £20bn bridge crossing the Irish Sea, as well as another one across the English Channel, which experts say could cost £120bn.

However, a poll commissioned by Scape Group suggests that less than a quarter (24%) of Brits think the economy would benefit from spending £140bn on two ‘Boris Bridges’.

Around 58% of British adults thought the bridges were ‘vanity projects’.

Four times as many Brits would choose to build underground systems for the UK’s most important cities over the Boris Bridges, the consultancy group found.

Around 75% also think the UK’s investment in metro systems is too focused on London.

‘Poor transport infrastructure is hampering our productivity – road congestion alone costs our economy £9bn a year. Infrastructure is vital to the effective and efficient functioning of society,’ said Mark Robinson, Scape Group chief executive.

‘Investing in underground systems across the UK would be an effective way of creating a productive and functioning workforce — and levelling the playfield with our European peers.

‘The UK’s ability to compete on the world stage will be challenged outside the European Union.

‘As an open market economy, the country has benefited from overseas investment, and with its future trading position with the rest of the world unknown, it is essential that the UK is better prepared to retain its global competitiveness. This could help to make the UK match fit for Brexit.’