Independence could have a "disastrous" impact on jobs in Glasgow, the Labour leader of the city council has claimed.
Councillor Gordon Matheson said that with a vote on Scotland's future to be held in 2014, there was a "climate of fear" amongst businesses in Glasgow.
He said there would be a "massive impact" on employment in the area if Scots did decide to leave the UK and become independent.
Mr Matheson warned jobs could be lost at the shipyards while business tourism in the city could also suffer.
The Glasgow City Council leader said: "Many companies have told me directly that the uncertainty of constitutional change is having a negative impact on their business. Independence would have a massive impact on employment in Glasgow. 4,000 jobs at Glasgow's shipyards would be lost, given the inevitability of the departure of significant employers such as BAE Systems."
As well as that, he said: "Thousands of jobs reliant on hospitality and tourism would be put in danger."
Mr Matheson said: "One of my greatest concerns is the potential collapse of our business tourism sector. This is worth hundreds of millions of pounds each year to Glasgow and the majority of this business comes from the rest of the UK. Let's be clear, UK organisations do not hold UK conferences outside the UK. The consequences for local jobs in this area would be disastrous."
Mr Matheson spoke out after giving evidence to members of the House of Lords, who were in Glasgow to hear about the possible economic impact of independence. The Lords Economic Affairs Select Committee was in the city the day after it met in Edinburgh.
On Wednesday, former chancellor Alistair Darling, who is now heading up the campaign to keep Scotland in the UK, had called on big companies and institutions to get involved in the debate before the 2014 referendum.
"I do hope people who have got a view about what happens in our country, whether in business or in individuals, speak up," he said. "There's no point keeping quiet then saying 'I wish I'd said something'. That will not do."