Tree surgery has no single mandatory registration in the way gas work has Gas Safe. There is no legal register you can check, which makes the checks you do yourself more important.
It is also genuinely dangerous work. A climber with a chainsaw working above your house, your neighbour's conservatory and possibly a public footpath is a serious undertaking, and the gap between a competent crew and an uninsured operator with a saw is wide.
Certificates to ask about
Chainsaw certificates. NPTC or City & Guilds units covering chainsaw maintenance and cross-cutting, felling small trees, and for anyone working above ground, chainsaw use from a rope and harness. Ask which units the climber holds.
Aerial rescue. This is the one to insist on. It certifies that the crew can get an injured climber out of a tree. A climber working with a groundsman who cannot perform an aerial rescue is a serious safety gap, and a professional outfit will not operate that way.
Arboriculture qualification. A Level 2 or 3 qualification in arboriculture, or a degree for consultancy work, shows knowledge of tree biology rather than just cutting technique. It is the difference between someone who can remove a branch and someone who knows which branch to remove.
Insurance
Ask for public liability cover and ask for the figure. At least £5 million is normal for tree work, and many firms carry £10 million.
This is not box-ticking. Tree work goes wrong expensively: a dropped section through a roof, damage to a neighbour's property, or injury to a passer-by. An uninsured contractor leaves you exposed as the person who commissioned the work.
Ask to see the certificate and check it is current. Ask about employer's liability too if they have staff.
Trade bodies
The Arboricultural Association's ARB Approved Contractor scheme involves an assessment of work quality, safety and business practice, and is the strongest single signal available.
It is not the only one, and plenty of competent small firms have never applied. Treat it as strong positive evidence rather than a requirement.
Practical checks
Ask what they intend to do, using the proper vocabulary: crown reduction, thinning, lifting, deadwooding. A contractor who talks about "topping" a mature tree is offering something you should decline.
Ask how they will handle TPO and conservation area status. The right answer is that they will check before quoting and will not start without confirmation. Someone who shrugs at that question is someone who will leave you facing the prosecution.
Ask about waste, parking and access. Realistic answers indicate someone who has thought about the job.
Ask for recent local work you can look at.
What we do and do not verify
Our listings are compiled from public Google Maps data and filtered to businesses rated three stars or higher with at least three reviews. Tradespeople who submit their own details are reviewed before publishing.
We do not hold certificates, insurance documents or qualification records for the businesses listed here, and we do not verify them. Ask to see them yourself and confirm anything that matters directly with the contractor before work starts. For tree work specifically, the insurance question is worth asking every time.