Huge double-helical gear cutter believed to be only one of its kind in the UK

This double-helical cutter which made gears for £200m polar research vessel RSS David Attenborough is believed to be the only one of its kind in the UK.

The cutter, which is around 60 years old, can make gears up to a huge 102 inch diameter and has helped in the production of Transport for London escalators and crushers for quarrying. Pentag, based in Chesterfield, Derbyshire, own six gear cutters which cut at a variety of different sizes - but their 'Sunderland 27SDH Spur & Double Helical Gear Planer' is believed to be the only one in use in the UK.