The Government is being urged to spend billions of pounds boosting business as firms cope with the aftermath of the vote to leave the European Union.
In its submission ahead of next month's Autumn Statement, the British Chambers of Commerce (BCC) warned that concerns over a slowing economy have intensified because of Brexit.
The business group called for a series of measures, including reform of business rates, investment in housing and broadband and more help for smaller firms.
The Chancellor should also pledge not to introduce any other significant costs on business for the rest of the Parliament, said the BCC.
Director General Adam Marshall said: "The Autumn Statement gives the Government a great chance to set the tone for its relationship with British business, by pulling out all the stops to support investment, infrastructure improvements, and business confidence.
"The Chancellor made the right move when he signalled his willingness to use historically-low interest rates to invest prudently to support growth, and he has a golden opportunity now to use this fiscal flexibility to 'crowd in' business investment.
"Plans to lower business costs and support investment would help firms take risks and seize opportunities in spite of the ongoing uncertainty surrounding the Brexit process.
"Westminster must do everything in its gift to improve the business environment, and firms will repay that backing with investment, hiring, training and export growth."
The BCC said its proposals ahead of the November 23 statement would cost £4.6 billion a year, equivalent to 0.6% of total government spending.