The Coronavirus Act 2020 is a temporary law that was bought in last year to deal with eviction issues during the pandemic. It applies to all parts of the UK. In Scotland, for example, to give a no-fault (see * below) /s21 eviction notice, the landlord must give the tenant 6 months notice (this stands for any notice given in Scotland before the end of September 2021 - at which point it may be reviewed), before s/he can start legal proceedings to evict you.
Your landlord is chancing his luck.
More information can be found here
As a side, your Landlord dropping around without notice is, if you presumably have a standard Assured Shorthold Tenancy, contrary to your tenancy agreement. The landlord must give you 24 hours notice before visiting.