British measuring tape

A British measuring tape from the 1930s. The measuring tape is made in the imperial system, with inches on one side and feet on the other. Its length is (I think) 50 feet (marked 5S). On the measure itself there are red markings "LONDON" and "SAGENF" "SACENF" "SAGENE" or "SACENE" (I am not sure due to the slight damage to the letters (but it is most likely "SAGENF"). Additionally, it has hand-written numbers in some places.