Health Desk: 07 February 2018: A number of beauticians in London are performing illegal teeth-whitening procedures, which can leave patients in crippling pain if they go wrong.
One place was secretly filmed by BBC London using illegal levels of the hydrogen peroxide at a strength of 25%.
The maximum legal strength useable by a registered dentist in the UK is 6%. If used incorrectly it can cause tooth loss, burns, and blisters.
The General Dental Council (GDC) has seen illegal treatments rise, it said.
Only dentists and registered professionals can do the procedures on customers with dentist prescriptions.
Whitening products available on the high street may contain up to 0.01% of the chemical.