Picture of testing device showing the current flow from a cable: https://ibb.co/YbqtgVX
Anything attached to the macbook port is causing shock on the exposed parts while it is plugged into that charger.
I wouldn't call it safe. If you read some of the bottom answers, they also elaborate on the same topic. Furthermore, I don't live in UK and there can be different electrical standards in terms of wiring.
I don't face this issue while using the grounded charger hence it is limited to apple charger which I double checked for missing ground support.