Sheffield must increase its productivity or risk missing out on trade opportunities when Britain leaves the EU, councillors have been warned.
Sheffield Chamber of Commerce's executive director Richard Wright said the Brexit vote would bring opportunities for the city to grasp as well as risks - although it was too early to tell exactly what would happen.
But he told councillors that the city needed to look at itself before worrying about external influences.
"We don't create enough wealth," said Mr Wright at the council's economic scrutiny committee meeting on Wednesday.
"Part of that is we are not productive enough.
"I think Sheffield is going to struggle at this moment. We could do very well, but if we don't do the right things it could go very badly.
"We must focus on our excellent areas around manufacturing, healthcare and creative digital."
Mr Wright said there would be opportunities as well as threats, particularly with new trading partners.
He predicted the 'Asian century' and a big shift in economic strength that would drive trade. Sheffield already has a 60-year investment deal with a Chinese company.
But he told councillors the chamber of trade was constantly lobbying the Government on trade, the labour market and funding for research.
Urging councillors to grasp opportunities, he said: "Things like the Olympic Legacy Park and the Digital Campus are very good things for the longer term for Sheffield."
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