Reminds of an inciden last year when we were doing a Telemetry Compliance Review project for Anglian Water.
I received this "urgent" phone call from one of the Guys to say they had lifted the Steel covers from a sump pit in a remote Sewage Pumping Works (SPW), the Anglian Water engineer was panicing as this snake appeared from steps into the pit and prompty made a move to strike at him. Julian used his Camera Phone to take a few picture to us in the office in an attempt to identify it.
Another Anglian water engineer said is wasn't a UK snake as it was about 4ft long but as thick as a mans arm...with the description we had, the only snakes we could identify of that size were all mebers of the Viper family, and the closest was a deadly Gabbon Viper.
Needless to say the Guys were in a bit of a panic as people tend not to encounter even our native snakes, let alone highly poisonous ones.
Eventually the Police arrived with a Vet, they managed to capture the snake about 15 minutes after they arrived.
When it was identified it was a shock, it was certainly a deadly viper..but not a Gabbon Viper, but our very own Adder.
The snake was taken to a Zoo and the keepers identified as a very mature Female which had to true full size, apparently it is very rare to find one of this size, and it's markings were of the darker variety that is usually seen so most poeple tend not to recognise them.
It was interesting to find out that even though this was "only" an Adder, it's bite would contain enough venom to make a healthy person very ill for a few days, and anyone with a heart problem or similar health issue could easily be killed by it.
Until then I never knew Adders could be dangerous...Seems that they have extremely effective and deadly venom, but for some reason it doesn't effect humans in the same way it effects Rodents, reptiles etc that they feed on..Thankfully.
Julian had some serious ribbing for a couple of months over that incident