The “Cosmetic Products (Restriction of Chemical Substances) Regulations 2024” was published on 3 April 2024.
It introduces new maximum concentrations as follows:
• In toothpaste: 0.1%
• In mouthwash: 0.001%
• In leave-on oral care products: 0.001%
• In other leave-on and rinse-off products: 0.8%

These provisions (which are slightly different from those that have applied to all products in Europe since 1 January 2024) apply from 24 February to products placed on the market.
Products already on the market may continue to be so until 24 June 2025.

Sources
• Le Royaume-Uni publie de nouvelles restrictions pour le BHT, CosmeticOBS, 8 April 2024
• Ingredient Sheet - BHT, CosmeticOBS