Sunil Kumar has a safe in the wall of his Wharf Street restaurant. Trouble is, he can't open it and has no idea what's inside.

It's a Thomas Skidmore safe, and a quick Google search reveals the finer details of the antique that may be worth anything from 240 to over 320 US dollars.

Sunil's locked up safe at at The Curry Hut. Photo: Andrew Campbell.

Thomas Skidmore & Sons made their safes between 1850 and 1920, but there's no indication which business installed the safe at The Curry Hut at No.20 Wharf Street.

Sunil's operated the restaurant since January, but only recently became curious about the safe and its possible contents.

Located under the stairs beside a concrete pillar, access to the safe is prevented from both the back and the side.

And unfortunately, his attempts to remove two brass screws behind the covering plate over the lock have proved unsuccessful.

The online locksmith is happy to appraise the safe, but requires high resolution interior and exterior photos, which are unable to be provided because the safe is locked and there is no key.

'”Thomas Skidmore & Son Wolverhampton, Fire and Thief Proof Safe Makers” is the branding cast into the door.

However, Californian locksmith Terry Andreasen says the fire proof fill is little more than a mix of sand and sawdust, which will offer very little protection to documents in the event of a fire.

During the mid-1800s to early-1900s, there were several hundred manufacturers making similar safes in four towns across England.

With the exception of the handle, name plaques, locks and key hole covers, these safes were virtually identical, says Terry.

Containers over 100 years old are considered Antique, while items that are 50-100 years old fall into the ‘collectible' category.