Sheffield steel
From Tardis Wiki, the free Doctor Who reference
Sheffield steel was steel made in Sheffield.
Sheffield was a notable producer of fine cutlery (PROSE: The Also People) made from Sheffield steel. (PROSE: Transit, Sky Pirates!)
The Thirteenth Doctor's handmade sonic screwdriver was partly made from Sheffield steel. She used actual spoons in the process of making it. (TV: The Woman Who Fell to Earth)
