I've had similar and the best thing to do is pull over, get your PPE on and speak to the guys. We have a moral duty to act that doesn't turn off when we clock off. You don't have to be agressive. If they ask you who you are say you work in Health and Safety. Don't forget to smile!! :)

I have seen roofer walking all over ACM roofs 6m off the ground with no edge protection or harnesses. I phoned the local HSE who thought they might be able to get there 'tomorrow'. They had gone two hours later.

From the scenario described, I share jfw's view that the trio seen are most likely to be metal thieves, though it's not quite clear why one of them entered the manhole. Theft of all types of metal, including cast iron covers for drains and manholes, continues to rise in the UK and the people who commit it are evidently ruthless and have no regard for anyone their actions may endanger or affect. This includes road users, including cyclists who are particularly at risk from the openings left by the theft of roadside drain covers. Metals which form part of war and other memorials, even in town centres, are also vulnerable, as shown by the recent theft of the memorial plaque to the 2 boys who were killed by an IRA bomb in Warrington. Therefore, I think the best action in such circumstances is to phone the police as soon as you can with details, including why you think the people seen are criminals and not contractors (i.e. no sign of any PPE and no warning signs for other road users.) If you think you can get one or more photos of the activity WITHOUT putting yourself at risk of being spotted by the people involved, they may well be of help to the police, etc. regarding any subsequent investigation. Even jotting down a registration number of the vehicle involved might help. Though there's no guarantee of a rapid response from the police, they are surely the best people to contact regarding 1) the possibility that a crime is being committed and 2) taking appropriate measures to make the location safe if necessary. The police will also know how to contact the local highway authority organisation at any time for practical action like signage, barriers and, sooner or later, replacement manhole covers. Despite what some OS&H people might think, the HSE is not an emergency service and has neither staff nor other resources to provide a 24/7 response. Even in the event of a major incident like Buncefield, it would take some time for HSE to arrange for relevant inspectors and specialists to attend the location involved and start liaising with the police and other organisations with a 24/7 emergency response remit.

Agree, if safe to do so (for you) - try and get as much information about the van and it's occupants (registration, make and model, what they looked like) plus exact location if possible then call the police. Explain the serious nature of the incident i.e. potentially life threatening to the person in the manhole and accident waiting to happen etc.. For good measure, call the HSE and inform them though unlikely they would investigate unless the van had been marked with the company logo and "how's my driving - ring....." sticker on the back!

Do not let such people see your number plate or any other type of identification as I know for certain that if they are real players they have access to number plate owner details! I know of a case where people were visited at their home addresses!!! Morality does not come into it; if it did both the police and the HSE would be adequately financed etc.

who you gonna call? - GhostBusters:)