Espacenet (http://ep.espacenet.com/)
European Patent Office database. Data includes some countries outside Europe.

Derwent Innovations Index (http://www.isiknowledge.com/)
Worldwide patents database. Please note that this online database can only be accessed when using the Inventors’ Info Point website at a participating Manchester library.

US Patent Office (http://www.uspto.gov/patft/)
US patents full text and full page image databases.

DEPATISnet (http://depatisnet.dpma.de/)
German Patent Office database. German patents plus many other foreign patents.

UK Intellectual Property Office (http://www.ipo.gov.uk/p-find-number)
Is a UK patent in force or lapsed? Can only check under application number or published patent number for a particular patent.

International Patent Classification (http://wipo.int/classifications/fulltext/new_ipc/)
IPC7 English version. International classification scheme for patents used by most databases.

British Library Patents Information (http://www.bl.uk/collections/patents.html)
A major gateway site with information and links to patent websites.

Chartered Institute of Patent Attorneys (http://www.cipa.org.uk/)
The professional body for UK patent attorneys.

Institute of Patentees and Inventors (http://www.invent.org.uk/)
A not-for-profit association for inventors.

Other patent databases and information websites (http://www.bl.uk/collections/patents/othlinks.html)
Many other databases and sources of information on patents available from Information page provided by the British Library.