There was a basket of thick red wool and two pairs of large knitting needles at the start of University College London’s cleverly curated exhibition, Witnessing Terror: French Revolutionary Prints 1792–94. Visitors were invited to contribute their own lines of stitches before picking up a copy of A Tale of Two Cities, in which Dickens fictionalised the tricoteuses, the women who gathered around the guillotine knitting and waiting for heads to roll.