http://www.hse.gov.uk/enforce/hswact/index.htm IMHO Section 3 applies - you are effectively a contractor and the company will be vicariously liable for your actons.

Talk to your insurers as I would be supprised if they covered a none competent person to undertake such work irrespective of their status e.g. employee, contractor or volunteer and as its an employee the 'gain' by your company could be pushed by a good barrister etc to cover this activity as an employee activity The type of tree must also be considered as some cannot easily be disposed of and personally I would not allow any arbourist work to be undertaken by a none *competent person [* competent in this case would be somebody who has all the appropriate training [NPTC etc] + experience + PPE etc] If your employee is competent [and acts as such on the day inclusive of disposal -as leaving on the ground to rot may not be suitable] and your insurers are OK then the action is probably allowable noting that H&S is here to ensure business continues NOT to stop business

Davimor. Why is it being done in the employee's own time. Is it because they want the wood? i.e they are requesting to do it.

I sort of know what you're saying, but I don't think that establishing liability is as simple, clear cut, or straightforward as that, but is rather dependant on the circumstances of the case.

Jeds your summary is relative to my simplified account. I would be going along these lines if it was my situation then you are doing what is reasonably practicable in the circumstance. You only have to look at cases where children enter constructions sites, they have make sure they secure the site to a reasonably practicable level. I think there is possibly a moral responabilty in this case as well as legal one.