This chapter looks at the UK in terms of BPE practice. The UK has unique housing construction in terms of its existing stock and the manner in which homes are built, renovated and managed over time, all of which conditions how BPE has developed there. UK housing remains exceptionally diverse in tenure, construction, form, condition and age, which presents a challenge for BPE in terms of simplifying and standardising methods. Contractual arrangements in UK housing have a major impact on BPE in terms of the different protocols that affect the continuity of BPE processes. Contracts tend to fall into two types: 'traditional' and 'design and build'. A baseline BPE monitoring exercise before the retrofit can verify the improvements made and indicate what additional retrofit improvements may be needed, such as larger windows, if the lighting quality is poor. The political context of BPE is important to understand, and is highly contingent on the initial set-up of the study.