Sir: Sam Clarke's letter, which you published (10 June) under the heading "Biotech patents hamper research", betrays a misunderstanding of the patent system and the proposals contained in the draft Directive on the Protection of Biotechnological inventions.

Patents do not hamper research. Many jurisdictions have a statutory mechanism to give effect to this principle. In the UK for example, the Patents Act 1977 exempts from infringement something which "is done for experimental purposes relating to the subject-matter of the [patented] invention". What a patent does is to enable the proprietor of an invention to control for a limited period of time its commercial exploitation, and rightly so; without patents, plagiarism would be rife, innovators and their backers would be denied the often necessary incentive to invest, and proprietors of inventions would resort to the only (and imperfect) alternative of trade secrecy, thereby massively inhibiting research.

The draft Directive would do nothing to remove the public's (or a competitor's) ability to seek to revoke a patent which they believe has been wrongly granted, using the procedures laid down in the Patents Act 1977 or the European Patent Convention.

ANDREW SHEARD

Patent Attorney

Kilburn Strode

London WC1