A builder nicknamed the King of the Cowboys faces jail after being convicted yesterday of defrauding pensioners out of more than #70,000.

William McPhee charged pensioners from the West of Scotland massive amounts for doing roofing and roughcasting jobs which he either botched or failed to complete. Many of the jobs were not necessary in the first place.

Yesterday, after a six-week trial, McPhee was found guilty of defrauding 16 victims between 1997 and 1998 by carrying out unnecessary repairs, working to a poor and unsatisfactory standard, and charging them grossly in excess of a reasonable price.

His oldest victim was 91-year-old Mary Hood, from Newton Mearns, who was charged #20,100 for work which should have cost between #800 and #850.

Instead of renovating her roof, McPhee, 37, covered it in green masonry paint to make it look as if the tiles had been renewed.

Glasgow Sheriff Court heard that five years ago McPhee was living in a caravan in Motherwell. At the time of his arrest he had a mortgage-free #130,000 house in Castlecary Road, Castlecary, and a #32,000 Mercedes.

To keep one step ahead of irate customers, police, VAT, and Inland Revenue investigators, illiterate McPhee registered his businesses in Wyoming, USA.

In the dock with McPhee was his nephew, Thomas Jr, 19, who was described by Miss Lesley Thomson, prosecuting, as his apprentice fraudster.

McPhee Jr, who lives in a caravan in a travellers' site in Maryhill, Glasgow, was found guilty of four of the charges involving frauds totalling #10,000. Earlier in the trial two other members of the McPhee family, McPhee's wife, Elizabeth, 38, and McPhee Jr's father, Thomas McPhee Sr, 43, who also lives in a caravan in Maryhill, were released when the prosecution dropped charges against them. Thomas McPhee Sr had been accused of building fraud charges, and Mrs McPhee of resetting thousands of pounds from pensioners which she lodged in her bank accounts.

After yesterday's verdicts Sheriff Kenneth Maciver called for reports before sentencing William and Thomas McPhee on March 2.

He told William McPhee he doubted whether his maximum sentence of three years would be adequate, implying he is considering sending him to the High Court for sentence. The sheriff said: ''You have been convicted of a catalogue of mean and despicable frauds in which you systematically targeted and defrauded old and vulnerable people who will receive the protection of the law.''

He said the frauds were of a substantial amount and although they amounted to #80,000 on paper he calculated that the victims had personally lost #60,000 of cash which they could ill afford. He added: ''Some of them had to arrange substantial loans in order for you to line your pockets.''

After McPhee's conviction the Crown served him with a confiscation order warning him that he could be stripped of all his assets, including his house.

Sheriff Maciver said he was considering a compensation order. He told McPhee: ''If you have any money I urge you to open an account with your lawyer with #60,000 which might mitigate your sentence, but not in a huge way.'' The sheriff refused bail.

McPhee was brought to justice thanks to Operation Hamelin, the biggest operation in the North of England and Scotland to trap cowboy builders and bogus workmen. McPhee ran three companies, A & M Roofing Services, A to Z Roofing Services, and Alltech Roofing Ltd. He produced wildly inflated estimates, costing jobs by sizing up the vulnerability of each customer and working out how much he could get away with. He invariably asked for advance payments before work began, and even took pensioners to the bank so that he could get his hands on the cash quicker.

One victim, retired chemist Andrew Jenkins, 83, of Irvine, told Miss Thomson how he thought the workers were okay as they were doing a job for his neighbour. Mr Jenkins was asked for cash in advance and he was driven by Thomas McPhee Jr to the bank where he withdrew #750. No work was done on his roof, which had earlier been damaged by the McPhees, and he had to pay a roofer to repair it.

Dementia victim William Wilson, from Coatbridge, paid cheques for #6900 and #1000 to McPhee for work which should have cost a few hundred pounds.

The jury heard a catalogue of stories. One of McPhee's favourite tricks was to claim a flat roof needed re-felted when it did not. Instead of ripping the old felt he simply put bitumen on top and then covered it with chippings.

Ms Elizabeth Mitchell, 64, from Gartcosh, who had given thousands of pounds for a totally unnecessary roof repair refused to pay any more. McPhee raised an action over a cheque which she cancelled having been legally advised that the details of his shoddy workmanship could not be part of the case. Ms Mitchell's bank account is still frozen.

McPhee's empire collapsed when he began a roof job at Graffham Avenue, Giffnock, Glasgow, the home of Mr Andrew Brown, 81, and his wife, Janet, 73.

Their neighbour's brother-in-law is a roofer and, on seeing the work, he took photographs. A major police investigation began. Customers were tracked down and a surveyor inspected each job.

Police uncovered a smoke screen of trickery. His home phone was under his wife's maiden name and his business premises were located at two answering service offices, one in Hope Street, Glasgow, and the other in Barrack Street, Hamilton. His van had removable signs.

There were no business records, except for a few papers found in his wardrobe, and there were no bank accounts in any of his company names. Most of the money was paid into his wife's private accounts.