The chief executive of Next and prominent Leave campaigner Lord Simon Wolfson has warned that the British economy is "finished" if the Government pursues an isolationist Brexit course.
The Tory peer told the Press Association that the referendum vote was about UK independence, not isolation - adding that Britain is setting itself up for economic failure if it closes itself off from the rest of the world.
"I think the hard, soft Brexit language is unhelpful, and what we should be talking about is whether we have an 'open' or 'closed' Brexit," he said on the sidelines of a press conference on Thursday.
"Britain voted for independence, it didn't vote for isolation and so we have a choice: are we going to choose to build an open, global-facing economy, or one that's closed and isolated?
"If we choose the latter, then our economy is finished. If we choose the former, we stand a chance of flourishing greatly."
It comes after Theresa May's Government indicated it would embark on a so-called "hard Brexit" by introducing migration curbs and stopping the free movement of EU citizens into Britain.
EU leaders have stressed that free movement is a condition for accessing the bloc's Single Market.
Lord Wolfson made the comments shortly after announcing that the £250,000 Wolfson Economics Prize would be awarded to the best solution for funding and overhauling the UK's road network.
The Tory peer - who was a prominent supporter of the "Leave" campaign - stressed that infrastructure investments will be essential for keeping the economy growing over the next five to 10 years.
"Things like roads, housing....these are the things that could stimulate growth and make up for some of the economic shock that will inevitably be involved in Brexit," he said.
Sir John Kingman, who is the chairman-elect of Legal & General and a panel judge for the Wolfson prize, suggested that Britain's infrastructure is decades behind.
"This problem...has preoccupied British governments certainly for as long as I worked in them, and I think before that," the Treasury's former permanent secretary told the Press Association.
"The fundamental problem is that the roads system is incredibly important for the economy, but the investment in it has to compete will all the other calls on public expenditure."
But Sir John gave a nod to Theresa May's Government, saying the Prime Minister as well as Chancellor Philip Hammond have "made clear that they understand the importance of infrastructure".
Speeches made at the Conservative Party conference earlier this month pointed to investment plans for housing and transport.
But Lord Wolfson has warned the Government against embarking on "glory" projects that benefit a select few.
Looking ahead to the Chancellor's Autumn Statement, Lord Wolfson said: "The thing I'm hoping for most is that we don't go for...very expensive glory projects that benefit a relatively small number of people, and that the Government comes up with a better way of assessing the investments that they make."
He added: "If the Government invests in bad infrastructure - infrastructure that doesn't pay for itself - then that will destroy wealth, it won't create it."