With an estimated personal wealth of between £1bn and £2bn, derived principally from his family's supermarket empire, the science minister has been able to spend vast sums in pursuit of his twin passions, science and politics.

In the 1980s the then plain David Sainsbury bankrolled the Social Democrats and was a particular admirer of the party's leader Lord Owen.

However, he switched horses to Labour when it moved toward the political centre following the collapse of the SDP/Liberal alliance.

According to some reports the supermarket tycoon has already given more than £3m to Labour coffers since Tony Blair became party leader in 1994.

This sum is said to have included £1m to help clear the party's overdraft after the victorious 1997 General Election campaign.

The peer has also shown his new Labour credentials by financially supporting Progress, the Blairite magazine.

Assets in trust

However, his financial interest in the development of genetically-modified food has aroused controversy at a time when the government has come under attack for not banning GM crops.

An invitation to join the government came in July 1998. Lord Sainsbury accepted and transferred control of his business interests to a blind trust - a standard practice for ministers to prevent any suggestion of a potential conflict of interest.

That portfolio included his holding in Diatech Ltd, the company which owns world-wide patent rights over a key gene used in the process of GM crops.

Even after Lord Sainsbury relinquished direct control of his assets he still managed to be named as the UK company director with the biggest annual equity earnings.

According to Labour Research, the independent research group, Lord Sainsbury earned more than £36m in dividends from his shares in 1998 - more than seven times that of his closest rival.

Blinded by science

Lord Sainsbury's interest in science was kindled at Cambridge University in the sixties. Although initially a history student he transferred to psychology because of a fascination with the breakthroughs then being made in the study of DNA.

The future government minister once said that if a fairy godmother were to grant him a wish it would be to become a Nobel Prize winner in plant genetics.