Help Snake

Today my daughter had the fright of her life. A small snake grey in colour wih a yellow band around the neck and with a black head crawled out from under the couch.  It was only about 4" long so not so big, but I have tried searching  to find out if it is poisonous or not, can anyone help. The house is in Cantabria near reinosa if that is of any help.
Thanks
Andy

Venomous snakes in Spain

There are a total of 13 snakes present in Spain of which five are venomous. These are:

Seoane's viper (Vipera seoanei - víbora de Seoane)
Asp viper (Vipera aspis - víbora áspid)
Snub-nosed or Lataste's viper (Viborade lataste - vibora hocicuda)
False smooth snake (Macroprotodon cucullatus - culebra de cogulla)
Montpellier Snake (Malpolon monspessulanus - culebra bastarda or de Montpellier)

OMG!
How scary is that!
Hope they can't climb, I live on the 3rd floor.............
Country walks in Spain may be out for me now!
I hate snakes!!!!!!

I actually saw what appeared to be a Montpellier about two and a half years ago. Was driving along a quiet residential street when across the road in front of me was a snake of about 1.5 metres to 2 metres long - it slithered off and I saw it in the rear view mirror - stopped the car and got out intrigued to see its back end disappear into some shrubbery - had come out of an empty overgrown plot of land where i guess it lived - built up area about 5 minutes walk to the beach in Marbella. Didnt really occur whether it was venomous or not but was far enough away to know I could get b ack in the car if it took a more aggressive stance but generally these things leave you alone if you leave them alone - hence i didnt go diving into the shrubbery in hot pursuit - too small to be a decent meal for a crocodile anyway.