A Mr. Derek Ffitch, of Royal Tunbridge Wells, writes to your correspondent with a question of such crushing triviality that one is almost obliged to answer it at length: why does the plastic ruler possess a long groove down its centre? Your correspondent, who has a small sherry about her person and a pressing engagement with the weather, nevertheless undertook to investigate, and has since spent three days in the company of rulers, civil servants and a laminated photograph. The groove, she can now reveal, is not a design flourish. It is a fossil.\n\nThe British ruler industry, for those who have not been paying attention, is a corpse that has been propped up in a chair since 1987, when the last great works at Smethwick - a town whose name your correspondent pronounces with a sherry in hand - closed its gates and sent its lathes to a skip in Wolverhampton. The plastic ruler to-day is made in Hong Kong, or Sheffield, or somewhere in between, and arrives in this country with the groove already cut into it by machinery that no living person has been trained to understand.\n\nYour correspondent telephoned the Department for Business and Trade on Tuesday morning and was informed, by a young woman who sounded as though she were working from home in a dressing gown, that the groove is ‘a legacy feature’. The phrase has the ring of a department that has given up. One poured a small sherry.\n\n## The groove is a relic of excise men and their folding rules\n\nAt the National Archives in Kew, your correspondent, wearing gloves and a look of forensic contempt, was shown a 1954 specification issued by the Board of Trade for a ‘folding rule for the use of excise men’. The groove, it transpires, was designed to accommodate a brass slider, by which the excise man might measure the depth of a beer barrel without putting his hand into it. The slider was discontinued in 1961. The groove remained, as grooves do, because nobody could be bothered to remove it.\n\n> ‘I typed the original specification myself, on a Remington,’ said Mrs. Enid Thribble, 91, of Orpington, a retired civil servant and the last living person to have read the document before your correspondent. ‘The groove was a matter of some controversy at the time. Mr. Hollis from the third floor said it would outlive us all. He was right about that, at least.’\n\nMrs. Thribble offered your correspondent a cup of tea, which was declined in favour of the sherry.\n\n## Neville Pout of Cleethorpes has other ideas\n\nCleethorpes, on a Thursday, is a town that has been left out in the rain and forgotten. Your correspondent travelled there by train, arriving at a crematorium on the outskirts, where she was met by Neville Pout, 63, a crematorium worker of thirty years’ standing and the proprietor of a collection of 412 rulers, which he keeps in a shed.\n\n> ‘The groove is a soul channel,’ said Mr. Pout, holding aloft a ruler that he had modified with a Stanley knife. ‘When the recently deceased is committed, the spirit needs somewhere to go. The groove lets it out. We cut a small notch here, at the end, so it doesn’t get trapped. It’s a kindness.’\n\nYour correspondent was sceptical, then noticed that every ruler in Mr. Pout’s collection was manufactured by a firm in Hong Kong that ceased production in 1998. She put this to him. He said that the firm had been chosen by the Crematorium Workers’ Benevolent Fund, which buys in bulk.\n\n## The Department admits the groove is pointless but expensive to remove\n\nA Freedom of Information request, submitted by your correspondent on a Tuesday and answered on a Friday, revealed that the Department for Business and Trade has known since 2003 that the groove serves no purpose whatsoever. A leaked email from a senior civil servant, Kevin Dullard, reads: ‘Removing the groove would require retooling at a cost of £4.2 million. We have decided to retain it and describe it as a heritage feature.’\n\nYour correspondent telephoned Mr. Dullard, who said he could not comment because he is ‘on leave until retirement’. She asked when that would be. He said, ‘Friday,’ and put the phone down.\n\n## Your correspondent makes a discovery about her own ruler\n\nBack at her desk, your correspondent examined the ruler she had been using throughout her investigation. It had a long groove. It also had a small blade at one end and a label reading ‘Stainless Steel Cheese Knife, made in Sheffield’. She had spent three days investigating a cheese knife. She poured another sherry and reflected that Neville Pout had died in 2019, and that she had been interviewing a laminated photograph in a frame, which had said very little, but had said it with conviction.\n\n## The groove remains, and so does the weather\n\nThe Department for Business and Trade has announced a consultation on the future of the groove, to be held in 2028. Neville Pout’s collection is to be auctioned in Cleethorpes, with proceeds going to the Crematorium Workers’ Benevolent Fund. Your correspondent intends to bid on a ruler, if only to have something to measure the decline with. It is raining. It will rain to-morrow. The groove, like the dead, will remain.