Hi Steve You would need to assess the risk from the type of platform and the type of work. A basic rule though is scissor lifts do not require it, but cherry pickers do. Here is a link to the HSE guidance, if you follow this you will be OK. http://www.hse.gov.uk/pubns/geis6.pdf Ian

Working at height regulations Mobile elevating work platform (MEWP) which either come as scissor lifts which move only up and down, and cherry pickers or boom type MEWPS, which can move in all ways. Both forms of equipment offer a guarded platform from within, the person or persons should normally work. In a scissor lift this safe working should negate the need for the wearing of a harness. In a boom the danger comes from movement of the platform and risk of hitting obstacles or being hit by other obstacles . The boom can act like a catapult in these circumstances so the wearing of a work restraint harness is then recommended. They also restrict the user not to climb out of the safe working platform

Steve, just double checking you understood the sound advice from Mgadd78 regarding restraint. It's the lanyard that attaches to the harness that gives restraint (or fall arrest) so just ensure they are wearing the correct one.

Agree with the scissor lift and cherry picker comments. There is only one scenario I know where it may not be sensible to wear a harness when working in the basket of a cherry picker...when working over water.

One other thing, mate although there is no specific legislation, always comply with Manufacturers Instructions. If they have an anchor point in a C/Picker and state a harness/lanyard must be worn in their user manual, then i would certainly ensure it is used. A Pasma instructor once said to me "Build a tower to the MIM and should it fall over, that will be your defence in court but build it the way you THINK it should be built or used and have an accident, that could be what they charge you with"