Allegations about PPM and Linda Watts began to emerge early in the year with claims from investors that deposits they had paid for city apartments had not been repaid.

Property owners also complained that PPM was not passing on rent money it had collected from tenants.

An investigation over several months by the T&A has revealed a string of disgruntled investors who claimed Mrs Watts had refused to pay back deposits and finders' fees on new property developments predominantly in Bradford and Yorkshire.

A group of investors allegedly owed £250,000 by Mrs Watts have engaged Leeds solicitors McKay Law to try to recoup their money.

Clinton McKenzie, of McKay Law, said: "We have spoken with the DTI and we're waiting for them to come back to us. They have said they do have some concerns. We're hoping to hear from them within the week."

Alan McMahon, of London-based Aldersgate Estates Ltd, said PPM had taken deposits and reservation fees on apartments in the forthcoming Eastbrook Hall renovation project without consulting the developers.

When Pontefract-based Asquith Properties discovered that Mrs Watts was selling apartments in Stonegate House, Bradford, without its permission, the company insisted that she sign a document giving assurances that she would no longer do so.

Asquith's Russell Baker said Mrs Watts appeared to have had a number of "pet" investors from whom she collected deposits and commissions.

PPM appears to have closed a number of offices recently including Yeadon, Duckworth Lane in Bradford and Chapel Allerton in Leeds.

Solicitor Clinton McKenzie, of McKay Law, said the concerns involved a number of Bradford properties including Eastbrook Hall and East Parade in Little Germany.

"Our clients have been informed that Linda Watts and PPM have no right to market some of these properties."

Investors who have paid deposits to Linda Watts for properties in Eastbrook Hall have spoken of their mounting concern over their dealings with the Bradford agent.

Bill Liddy, of Gosforth, Newcastle, who paid £5,000 to reserve two apartments in Eastbrook Hall, said: "A number of people who've made substantial investments have asked for their money back but haven't been paid. I had a cheque that bounced and then I was promised BACS transfer. I'm not alone.

"We've engaged lawyers to pursue her but she has threatened to report them to the Law Society."

Mr Liddy has shown the T&A a copy of a cheque for £5,183.92 which he said had not been cleared for payment.

Investor Colin Megson has provided the T&A evidence of a cheque for £9,848.27 from PPM which he said was also not cleared.

Another PPM client, Steven Giles, of Bradford, who uses the firm to collect rent on a flat he owns in the Meanwood area of Leeds, claimed that Mrs Watts has refused to pass on two months' rent at a total of £874.50.

After frequently contacting the company he had noticed that some branches had closed down. He said on April 18 he was sent a cheque for the outstanding amount but this had not been cleared by the bank on April 25.

When approached by the T&A in May, Mrs Watts strenuously denied that she acted improperly and confirmed that she had referred McKay Law to the Law Society. She also insisted that no cheques from PPM had ever been refused by her bank.

"I have an issue with several of the investors," she said. "I dispute the amounts and I do dispute the fact that we're refusing money to people. The properties are there for the investors and they aren't entitled to their money back.

"The market has slowed in Bradford but they made a business decision to invest in certain properties. I believe that PPM has been the victim. I strongly deny that we are refusing to pay people back.

"I'm absolutely confident that it won't be taken any further. These people are threatening and bullying me because they've changed their minds. We'll just have to wait and see what happens."

Brendan Gilfoyle, of Leeds-based business recovery specialists P&A was due to meet other directors today in a bid to rescue the business.

"We're looking at the possibility of administration," said Mr Gilfoyle.

"It seems to me that some sort of insolvency proceedings are inevitable. Whether that's driven by the directors or the creditors remains to be seen. But if the directors don't do anything the creditors certainly will."

PPM was set up in 2000 and grew into a company with an 18-strong team and five offices. In March it trumpeted the opening of its new headquarters in Peckover Street, Little Germany, and announced that it was advising city developers on everything from planning permission to market demand.

Members of Mrs Watts's family including husband Graham, brother Fred Ford and daughter Stephanie Would have directorships in the firms.