On starting my apprenticeship at Chatham Dockyard in 1959, I was told to 'forget all you've learnt about Fahrenheit and British Thermal Units etc., we're changing to Centigrade and Calories etc., and from then on I seemed to spend more time doing imperial/metric conversions than anything else.

Surely a 40 year changeover is long enough even for Vivian Linacre of the British Weights and Measures Association. Mr Linacre states - letters 7th January - that imperial measurements are widely used abroad, even Europe. Is he having a laugh? Imperial measurements are hardly used in this country. I would be hard pressed to think of a single British trade or industry that hasn't gone mostly metric.

In October '99, the £125 million Mars Climate Observer spaceship was destroyed because NASA mission controllers confused imperial and metric measurements.

A few years ago the windscreen of an airliner blew out when landing at a British airport - the pilot was torn from his seat and was sucked through the opening. He was saved by his quick thinking crew who managed to grab his legs. If this had occurred at cruising altitude the plane and passengers would have certainly been lost. The cause - a mix up with imperial and metric screws.

Another airliner in North America completely ran out of fuel in flight - the flight engineer thought he had to fuel in kilograms not pounds. The passengers and crew were lucky to survive a landing, without engines, at a disused airfield. The problems encountered by the pilot were later fed into a flight simulator - every pilot tested on the simulator crashed.

At the inquest into the death of a young West Country driver, the Police Vehicle Examiner stated that the tyres of the car were over inflated and suggested that the driver may have misread a dual reading tyre pressure gauge, putting 2.8 bar (roughly 41 pounds per square inch) instead of 28 p.s.i., making the car a death trap in the wet. He also stated that he had seen other instances of similarly over inflated tyres on crashed vehicles.

Australia and South Africa managed a complete change from imperial to metric in a matter of weeks. Please Mr Linacre give up your lost cause.

Ron Connor

Taormina,

School Road,

Pensilva.