Thieves smashed a hole in an exterior wall and removed bricks to break into a family firm in Sheffield.
They struck at Wentworth Pewter in Darnall between Saturday and Monday and stole six tonnes of pewter in sheet and circle form.
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The thieves bypassed the alarm system in the ‘well planned robbery’ and managed to flee the scene without being detected.
In a Facebook post Wentworth Pewter said the firm was ‘heartbroken’ at the raid.
The company, which was set up in 1949 and is based in Catley Road, produces handmade pewter metalwork from flasks and tankards to goblets, baby gifts, tableware and trophies as well as one-off commissions.
The firm’s Facebook post reads: “We are a little heart broken here. We were sadly broken into and our metal stock was taken - this was a well planned robbery bypassing our alarm system and gaining access through an external wall.
“It was definitely not a small loss - nearly six tonne of pewter sheet shapes and circles were taken.
“Pewter is not a common metal and not much use to anyone other then pewter giftware manufacturers. It should hopefully mean with a bit of help and luck it can be found.
“We have three weeks till Christmas and it is our busiest time of year. Although we have good stock and work in progress it will make life a little harder.
“We are a small, family run business with 20 highly skilled craftsmen and women who work hard and love what we do. It is gutting to think there are people out there that would do this to us.”
The company is offering a reward for information leading to the recovery of the stolen metal and the arrest of those involved.
Call South Yorkshire Police on 101.