Hi Huw - my pleasure

Dear all - for your reference please see below.
Portable Appliance Testing, or PAT testing as it is commonly referred to, has always been a bit of a grey area.
There has never been an official legal requirement to do PAT testing. The main need for having to do PAT testing is under the Health and Safety at Work Act 1974 (HASAWA) where employers have a “duty of care” to their staff and visitors.
The Electricity at Work Regulations (EWR) state “As may be necessary to prevent danger, all systems shall be maintained so as to prevent, so far as is reasonably practicable, such danger.”
So far as frequency is concerned, this can only be determined by the Duty Holder. Many companies view best practice to be testing every appliance every year, though this needn’t be the case if you manage the appliances and keep track of them.
The HSE did release some guidance on the frequency of PAT testing, as did the IEE (Institute of Electrical Engineers). However, this is only generic and is not necessarily suitable to each organisation.
The best advise I can provide is run a series of risk assessments for different types of equipment and different work areas. It is reasonable to suggest that a PC, which is rarely moved, provides a lower level of risk than that of a cordless drill that is obviously much more portable and much more likely to cause an injury through electric shock.
I recall some companies having testing spread over a 4 year period as follows:
Year 1 – test on ALL equipment
Year 2 – test on all HIGH RISK equipment
Year 3 – test on all MEDIUM and HIGH risk equipment and a visual only inspection on LOW RISK equipment
Year 4 – test on all HIGH RISK equipment
And then repeat the whole thing over again.
The most important thing is to have the risk assessments conducted so that you have a paper trail detailing the choices that have been made and why – so that it is clear the decision was based on a risk assessment and not just simply “not doing this year because I can’t afford it”.
The main thing to consider is, should the worst happen and you get taken to court for a faulty piece of equipment and they ask for PAT testing records, would you be happy to stand in court with your evidence and say that you took all “reasonably practicable” steps to reduce such danger. If you can satisfy yourself (or the Duty Holder) that the answer is yes then you should be able to rest easy.
You might want to consider speaking with NHS LA (the NHS Litigation Authority) as they may have more specific advice concerning PAT testing in the NHS. I know that they have key standards when it comes to managing medical devices but have not spoken to them about PAT testing and Electrical Safety Testing in general.
I hope this information has been of some help, but if anyone has any other questions, please do not hesitate to get in touch with me.
Kindest regards,