British Thornton was the premier maker of slide rules in the UK. Their earlier celluloid and wood rules were sold under the PIC brand but this one is all plastic.

The rule has 15 scales: LL2, LL3, L, A, D, S, T, and ST on the stock; B, CI, ISd, ITd, Td,  Sd and C on the slide. The layout is identical to the P 271.

The rules show slight signs of use but all in in very good condition.

A hard plastic case is provided.

A photo-copy of the original documentation will be provided.