The former wife of Nick Leeson yesterday postponed her wedding to her new love after learning that the rogue trader is seriously ill with cancer of the colon.

The 31-year-old financial whizz-kid, whose currency gambling broke Britain's oldest merchant bank Barings with losses of #860m, is seriously ill in a Singapore prison hospital.

He was diagnosed with the disease on Wednesday.

Lisa Sims - she has reverted to her maiden name - was with Leeson when he was arrested in Frankfurt en route to London.

She stood by him as he bitterly fought extradition proceedings to Singapore, bidding instead for his case to be transferred to London. Leeson was jailed in December 1995 for six years.

The couple began to lose contact in 1996 before finally divorcing last October.

Yesterday Ms Sims, 30, said she was in ''deep shock'' after hearing of her former husband's illness and sent a personal message of her love to Nick and his family.

Ms Sims was due to marry new love Keith Horlock, from Benfleet in Essex, at a luxury mansion house in Bexley, Kent, next Saturday.

But at 10am yesterday Ms Sims's mother, Patsy, called the country house owned by Roy and Audrey Grant and said the wedding was off.

Last night Mrs Grant said: ''Yes, they have cancelled. We received a phone call at 10 this morning cancelling it. I am not sure who it was but I believe it might have been her mother.

''All she said was they couldn't get their heads round what has happened and they are all in turmoil at home and can't think straight.

''And that they wouldn't have been able to enjoy the nice quiet wedding that they had planned.

''They haven't booked another date. They may be likely to go abroad to have a quiet wedding.''

The couple booked their wedding at Vale Mascal - which is licensed for weddings - about six months ago. They had planned to have chairs, tables and a marquee on the lawn, so their guests could enjoy champagne on the expansive lawns that stretch for five acres.

They would have enjoyed a civil wedding service and would have had a selection of CDs playing during the service.

They had booked the country house for two hours and planned to move on for the reception afterwards.

News of the cancelled wedding came as Leeson's lawyers launched a mercy mission to bring him back to Britain.

The legal moves to secure his release were given added urgency after doctors at Changi Prison, where he is being held, said the cancer has spread to the lymph nodes - raising fears it could quickly infect vital organs.

John Koh, the lawyer acting for Leeson in Singapore, has lodged a plea for early release on medical and compassionate grounds.

It is understood a presidential pardon would be required to bring the trader's early release.

The futures trader is more than two-and-a-half years into a six-and-a-half year sentence imposed for fraud offences after the spectacular collapse of Barings, one of Britain's most venerable banks, in February 1995.

Speaking from the Indonesian capital, Jakarta, Mr Koh said: ''An application has been made in order to allow Mr Leeson to return to Britain. We cannot say how long that will take or indeed whether it will be successful.''

Under Singaporean law, sentences can only be commuted by a direct pardon from the state's president, 62-year-old Ong Teng Chong, who is also suffering from cancer of the lymphatic system.

A spokesman for Changi Prison said no information on a pardon request was available, but added that pleas based on extreme illness could expect to be considered as quickly as possible.