http://ted.publications.eu.int
All purchasing by the public sector in the UK and the rest of Europe must follow the rules of the EU Treaty if above the EU thresholds:
Any company can apply for these contracts. The supplement containing tender information is in the Official Journal of the European Union (OJEU).
You can also phone The Stationary Office (HMSO) customer services on 0870 242 2345 for subscription to OJEU. Alternatively, you can view the OJEU at the above link.