Current UK law requires car, van and LCV drivers to have at least 1.6mm of tread across the central three-quarters of the tyre, around its entire circumference.
For trucks (vehicles exceeding 3.5 tonnes g.v.w), current tread depth legislation requires that they must have a minimum of 1mm of tread in a continuous band throughout the central three-quarters of the tread width and over the whole circumference of the tyre. The same regulation applies to regrooved tyres.
Meanwhile, for motorcycles over 50cc it is 1mm across ¾ of the width of the tread pattern and with visible tread on the remaining ¼. For motorcycles up to 50cc the law requires that all the grooves of the original tread pattern must be clearly visible.