This guide from the Information Commissioner’s Office (ICO) explains the provisions of the GDPR to help organisations comply with its requirements. The GDPR forms part of the data protection regime in the UK, together with the new Data Protection Act 2018 (DPA 2018). The main provisions of this apply, like the GDPR, from 25 May 2018. This guide refers to the DPA 2018 where it is relevant. In the longer term, the ICO plans to publish more guidance under the umbrella of a new Guide to Data Protection, which will cover the GDPR and DPA 2018, and include law enforcement, the applied GDPR and other relevant provisions.
Clicking the link on this page will take you to the relevant part of the ICO website.