INVESTORS' perception is invariably more influential than commercial reality in determining, the direction of any given share price. Witness the staggering appreciation in the share price of British Biotech during the week following "further positive results" in clinical trials for its much hyped anti cancer drug Marimastat. The drug is, designed to stop the spread of pancreatic and ovarian cancer, unlike others which attempt to kill tumours.

This minnow among pharmaceutical development companies, which has never sold a product - or made a profit, is now valued at more than £2 billion sterling following this week's 285p surge in its share price to £33.15. Early last year the equity could be bought for £4.30p. Such a valuation makes it worth more than several companies ala ready on the prestigious FTSE top 100 companies index. The company is running cumulative losses of £32 million over a two year period due to heavy expenditure on research and development.

For Mr Keith McCullagh, founder and chief executive, the scramble to buy shares has created paper profits of Lotto type proportions. His personal shareholding is now worth £25 million, compared to £3.3 million in February last year.

With small exploration companies considered a spent force, speculative money is now pouring into new millennium, high risk, high rewards enterprises such as specialised computer products - and designer pharmaceuticals. An investment thrill for cash rich buccaneers only, adventurous widows and orphans should stick to the occasional lotto ticket.