What age can a child stop using a booster seat in UK?

In the UK, a child can stop using a booster seat when they reach 135 cm in height or 12 years of age, whichever comes first. However, it is recommended that children use a booster seat until they are tall enough to wear a seat belt comfortably, which typically happens around 150 cm. Parents should ensure that the seat belt fits correctly across the child's lap and shoulder for optimal safety.