Contract Law

 - Treitel The Law of Contract, 15th edition by Edwin Peel, published by Sweet Maxwell
 - Contract Cases and Materials, by H.G. Beale, W.D. Bishop, and M.P. Furmston

General Data Protection Regulation (GDPR)

 - Directive 2016/679 - General Data Protection Regulation 

Liability

 - Civil Liability Act 1961 - Colloquially 1% Rule (Section 12). Joint and several liability.