Transport for London work with all the London boroughs to organise and fund free or subsidised cycle training for adults and children.
You can have training from the borough in which you live or work or study. It's worth checking the council website for each borough that applies as some offer a more flexible, pro-active service.
http://www.tfl.gov.uk/roadusers/cycling/11689.aspx
http://www.wandsworth.gov.uk/cycletraining
http://www.merton.gov.uk/living/transport-streets/roadsafety.html
http://www.cycleconfident.co.uk
http://www.cyclinginstructor.com
A good book is Cyclecraft by John Franklin ISBN: 978-0-11-703740-3 http://www.cyclecraft.co.uk/book.html
Cyclecraft should be readily available at your local library as should The Highway Code Revised 2007 edition which is also readable online at
http://www.direct.gov.uk/en/TravelAndTransport/Highwaycode/DG_069889