In reply to pec:
It's not correct:
https://www.lexology.com/library/detail.aspx?g=9b5ec155-0cde-4827-ad48-9a01...
From 1 July 2020 for new tenancies, landlords must ensure that electrical installations are inspected and tested by a qualified person before the tenancy begins.
From 1 April 2021, for existing tenancies, an electrical safety test will need to be carried out by 1 April 2021.
The Regulations oblige owners to carry out tests and comply with the 18th edition of the “Wiring Regulations”, British Standard 7671 (BS7671).
The electrical installations must then be tested every 5 years (or earlier if the safety report requires it).
What's more notable is that it appears to require compliance with Edition 18, which is going to require quite substantial work on older properties that have an installation with "grandfather rights" to one of the older Editions. Which will be most houses, because Edition 18 is quite new.
Post edited at 17:37