The group's quarterly business confidence monitor has found that while confidence remains substantially diminished after the EU referendum, there are “modest” signs of some recovery.
The ICAEW said that businesses had responded favourably to the rapid establishment of a new government under Theresa May, in particular.
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As a result, while it remains far below levels witnessed prior to the Brexit vote, optimism grew in the days after July 20.
Stephen Ibbotson, ICAEW director of business, said: “UK businesses are resilient and after the political shock of the referendum result, many are just getting on with delivering their business plans and moving forward.
“UK plc is grateful that the new Government was established quickly but decisions will need to be made swiftly to build confidence, which has been following a downward trend for the last two years.
“Encouraging businesses to invest as well as explore new markets has to be the immediate priority for the government whilst it develops its vision for the UK economy once we have left the EU.”