A vote to leave the European Union could plunge the UK economy back into recession, according to a former Labour Chancellor.
Alistair Darling was telling business leaders that Brexit would be "disastrous" for the living standards of working people.
In a speech to the annual dinner of the CBI in London, Mr Darling was saying: "When economic experts from Christine Lagarde to Mark Carney are warning of recession if we leave Europe, people should sit up and take notice of the scale of the risk we face.
"Recent experience and historic evidence shows that when our economy suffers this kind of serious damage, insolvencies, repossessions and unemployment, particularly among young people, all soar.
"Economic insecurity of the type being forecast would be disastrous for working people's life chances and living standards.
"Economists and economic institutions are queuing up to warn of damage to trade, growth, investment, our credit rating, and the pound.
"Collectively these warnings should sound alarm bells but in a desperate response, the Leave campaign always play the man not the ball."
Former Conservative party leader Lord Howard will criticise the CBI's record on the EU when he tells the event that lack of democracy in the EU was hurting business.
He will say: "At the moment, every UK business must comply with "single market" legislation, even though just 5% of British firms export to the EU.
"This is a system which has an inherent tendency to produce disproportionate burdens on small companies, impeding their competitiveness.
"If we Vote Leave we can take back the power to make our own trade agreements. At the moment, we have no trade deals with India, China, Brazil or even Australia and New Zealand. We have to wait for 27 other member states to agree before we can arrange a single trade deal.
'If we left the EU with no trade deal - inconceivable given the tariff free zone from Iceland to Turkey - our exports would face EU tariffs averaging just 2.4%.
"But our net contribution to the EU budget is equivalent to a 7% tariff. Paying 7% to avoid 2.4% is mis-selling on a scale that dwarfs the scandal of PPI."
He will say that the CBI called for full UK membership of the European Monetary System in 1987, which led to 15% interest rates in 1992, and later argued in favour of joining the euro.