John Longworth, Director General of the British Chambers of Commerce, told ITV News the government would need to take "radical" measures in a bid to end the "long term sluggish growth".
He called on the Chancellor to deliver "massive infrastructure development" and a "restructuring of business finance in the UK".
The Liberal Democrats have been setting out the points of difference between themselves and the Conservatives during the negotiations over the Autumn Statement.
Sources close to the Deputy Prime Minister, say Nick Clegg drew red lines and refused to allow the Chancellor to cross them.
The Lib Dems did not want benefits to be frozen as had been proposed. The Chancellor announced today they would increase by one per cent (although that is still below the current rate of inflation).
Neither did Mr Clegg sanction the additional £10 billion of benefits the Tories had been seeking, including restricting child benefits to families of two children or fewer. It is highly unusual for the Lib Dems to brief independently of the Conservatives after the statement by the Chancellor.
But they clearly want to claim credit for the policies which will go down well with their supporters.
We welcome today’s statement and we are encouraged by the Chancellors’ acknowledgement that small businesses need more help. We accept that bold actions are needed to boost the economy and we hope we are on the right road to helping small firms.
– John Walker, National Chairman of the Federation of Small Businesses
The Chancellor has listened to many of our members’ concerns, and has put forward proposals to address these issues - notably around capital allowances, more encouragement for investors to place funding in small businesses, and cancelling the 3p rise in fuel duty.
We now eagerly await further details on the small business bank which we have long seen playing a central role in opening up finance for small firms.
– Ian Stewart, Chief Economist at Deloitte
For the wider economy the worst is probably past. The independent Office of Budget Responsibility and most other forecasters expect the economy to grow modestly next year.
However, for now, at least, this looks like a choppy, fragile recovery.
Director General of the Confederation of British Industry John Cridland told ITV News he supports the Chancellor's Autumn Statement but added that George Osborne must "deliver on the ground for businesses".
The head of the Office for Budget Responsibility Robert Chote said the British economy is running three per cent below full capacity and predicted negative growth for this year.