An east London pie and mash shop dating from 1929, praised by English Heritage inspectors for its “exceptionally complete interior”, has been awarded a Grade II listing.

L Manze eel, pie and mash shop on Walthamstow high street still exists for its original purpose and has been given extra protection by the culture minister Ed Vaizey.

He said: “Pie and mash shops are as intrinsically linked to London as black cabs and beefeaters. L Manze’s in Walthamstow is a unique part of the capital’s heritage and is as relevant and popular now as it was when it first opened in the 1920s. It clearly deserves to be given Grade II-listed status.”

The shop joins around 345,000 buildings that have this level of protected status in England. Roger Bowdler, designation director for English Heritage, said: “Eel, pie and mash shops are a unique feature of the London scene and represent some of our oldest traditions of fast food. This 1920s example with its beautifully preserved interior is among the best of an increasingly rare kind and strongly deserves to be listed.”

Inspectors estimate that there are about 30 traditional pie and mash shops still in existence, concentrated in the East End and south-east London with a few outliers in Essex new towns and seaside resorts.

The Walthamstow shop is particularly beautiful. It was part of a successful chain established in the early 1900s by Michaele Manzo, a native of Ravello in southern Italy whose parents settled in Bermondsey in 1878. He effectively married into the business when he wed Ada Poole, daughter of London’s most successful pie shop magnate Robert Cooke, Manze’s friend and mentor.

The first Manze shop was opened on Tower Bridge Road, and is now the oldest of its kind in operation. Walthamstow was number 14, opened by Michaele’s brother Luigi, who employed the architect Herbert Wright to create what exists today. It was run by the Manze family until 1970.