Helen Lowe, from Edinburgh, died in November 1997 just short of her 100th birthday.

About half the money is likely to go to the taxman, with the rest divided among beneficiaries. But tracking them down is a problem.

Executor and second cousin Arthur Lowe, who is in his 70s, said she had relatives in the UK, Canada, Australia and South Africa.

"We have unearthed a number of relatives already and no doubt there are more to come.

Miss Lowe died in Edinburgh aged 99

"There could be dozens and we have to establish this before we can make any move. It is taking a lot of time and effort."

Miss Lowe was a pioneering career woman who became one of the first women chartered accountants in Scotland and started her own business in 1928.

Mr Lowe, from Edinburgh, said he knew she had been wealthy, but was staggered to learn the exact size of her fortune.

She had a portfolio of stocks and shares and owned a number of properties in the Edinburgh area.

"She was as bright as a button and continued to work right up until she died in November last year. She wasn't frugal so much as canny.

"She had a native Scottish driving power and ambition that would make her buckle down to a challenge - and it was a challenge in those days to become a professional woman."

Mr Lowe said he could not understand why his second cousin had failed to draw up a will after a lifetime efficient organisation.

"We simply can't work it out. She even had letters from her solicitors pleading with her to make a will and sign it

Her sweetheart died in World War I

"We don't know how many benefactors there will be. There is a genealogist piecing together the family tree and finding people who we have never even heard of.

"We think it will be a long time before this is disentangled."

Miss Lowe was not married because she was a "victim of the Great War", losing a sweetheart in the conflict.