This is a Thomas Walker fastening buckle.

Thomas Walker metal fasteners were one of the oldest manufacturing firms in the West Midlands. 

Established in 1867, this Birmingham-based company supplied the clothing industry for over a century.

Located in Kings Norton, Birmingham, they produced zips, buttons, waistband fasteners, belt buckles, and even surgical fittings."

These specific buckles were invented to replace buttons for fastening braces. However, as fashion evolved, the clamp-style buckle began to lose popularity and by the 1950s, more practical clip-on suspenders had replaced these buckles, making it easier for people to adjust their clothing.

Despite its long-standing history, Thomas Walker went into administration in 2010, ending an era of craftsmanship that once served the clothing industry.