We just got IPTG from Diagnostic Chemicals Ltd. They're in Canada, and I have no idea whether they sell to the UK, but they were charging US$250 for 25 g a couple months ago. The catalog gives these Internet addresses: Marketing Enquiries: sales at dclchem.com Technical Assistance: techserve at dclchem.com Order Desk: orders at dclchem.com Hope this helps, Midori