The production, possession and consumption of THC -and related substances- is illegal. This is because cannabis, THC vape oil and most SPICE are class B drugs under the misuse of drugs act, which means it is illegal to have or use them.
Possession of class B substances can result in a maximum of 5 years in prison and/or an unlimited fine.
Production of THC vape oil, SPICE and cannabis is also illegal. This includes the growing of cannabis plants, along with the act of adding THC oil -or similar substances- to juices in vapes. If caught, distribution of illegal class B substances can lead to a maximum of 14 years in prison, an unlimited fine or both. Distribution or supply does not just mean selling this, it also includes passing a vape containing substances to someone else.
It is no longer legal to sell disposable vapes in the UK.