To my eyes the letters appear to be 'LISBUR', which would surely have to be part of a word, with some of the letters lost.
As a UK find, a more likely possibility might be that the word in full was 'SALISBURY', which opens up many possibilities as either o location or a company/brand name. There was for example a company called Salisbury (both written that way and also written as Salisbury's for branding purposes) who made all kinds of bag and luggage-related items. Is it sufficiently tiny that it could be part of a twist-catch or some other kind of fastening for a handbag or small piece of personal luggage?