Britain has wasted an opportunity to lead Europe in nanotechnology because hundreds of millions of pounds has been held up by Whitehall, scientists claimed yesterday.

Although the Department of Trade and Industry is expected to announce more than £200 million of new money in the next month for the emerging field - which involves building machines on a molecular scale - leading researchers said the strategy could have been published months ago.

Currently, Britain spends about £50 million a year on nanotechnology. Japan spends almost £400 million a year, and the US will spend more than £500 million next year.