Sir

You report that the Wellcome Trust favours siting the new Anglo-French synchrotron source (Diamond) at the Rutherford Appleton Laboratory in southern England instead of at Daresbury Laboratory near Manchester (Nature 402, 451; 1999). I am concerned about Wellcome's statement that it is important to site Diamond close to the existing neutron spallation source (ISIS).

In fact, no protein-crystallography research is done on ISIS. Neutron protein-crystallography research is and will be conducted at the Institut Laue Langevin neutron source in Grenoble, France. I hold a Wellcome Trust research grant to work on both synchrotron X-ray protein- crystallography data collection and neutron protein-crystallography data collection. It has not been necessary to have X-ray and neutron sources at the same location — it is simply not a requirement.

I am surprised that I have not been asked my opinion by anyone on the question of the siting of Diamond. Not only am I the chairman of the Institut Laue Langevin neutron beam-time biology review committee, but I have also chaired synchrotron X-ray advisory committees for the European synchrotron radiation facility in France, Cornell in the United States and the Daresbury Synchrotron Radiation Source protein-crystallography beam panel.

I strongly support Daresbury as the site of Diamond. This vital project requires the vast body of experience among the staff at Daresbury Laboratory. The Rutherford Appleton Laboratory has its own expertise and is planning its own ISIS neutron source upgrades. But this is irrelevant to placing Diamond in the best UK location for its optimal, proper and successful development, which should be at Daresbury.

Finally, I warmly welcome the Wellcome Trust's involvement to the fullest extent possible in Diamond at Daresbury. The protein-crystallography programme on Diamond must be as vibrant as possible, given the importance of structural biology in the expanding fields of structure-based drug design and health care. The trust and the UK government research agencies are key players in this enterprise that should ensure the continuing international competitiveness of UK research and its pharmaceutical industry.