Confidence in Britain is faltering amid “extreme ideology” on both sides of the political divide, a business leader has warned.

Carolyn Fairbairn, director general of the CBI, set out a series of dangers she said could get in the way of a bright future for the country.

She told the business group’s annual conference in London: “On the right, we have the threat of — even preference for — no deal as the end point of our Brexit negotiations.

“For some on the right, this preference for no deal is driven by a zeal for something beyond this – and that is the wholesale deregulation of the UK economy.

“But I want to be clear that this is not what British firms, large or small, want.”

Companies want to improve the quality of good jobs, not diminish them and will do all they can to make Brexit work, she said.

“But when no deal becomes an ideology of its own, seemingly intent on ignoring the impact on jobs and livelihoods, then we have a problem.

“Meanwhile, ideology from the left is at least as damaging. The Labour Party is proposing the biggest programme of renationalisation this country has ever seen, at great cost, with uncertain returns to the taxpayer, and with no clear route to better customer service.”

Labour’s announcement last week to nationalise parts of BT was a “bolt from the blue”, which had “sent a chill through boardrooms at home and abroad,” said Ms Fairbairn.

She added: “Many firms are questioning whether their investment is safe, and some thinking are we next?

“These ideologies from both sides are causing great harm to our economy. Not just in the future but right now.

“To see this, you only have to look the effect on business investment, which has fallen in five of the last six quarters. Confidence in Britain is faltering.”