This afternoon my wife was sat reading in our garden, when out of the corner of her eye she saw a snake. It was between 3 and a half and 4 feet long (!), quite thick, muscular and sandstone in colour. When she moved to come in the house to tell me, it wriggled away quickly and out of sight.
Difficult question perhaps to answer without seeing it, but anyone any idea what kind it could be?

Did it have any obvious markings? If not it was probably a grass snake. They are harmless.

Pocoloca beat me to it, sounds just liek a grass snake we have some in the garden. Harmless

Or possibly a Montpelier, which are not so harmless!

If it had markings it might be a Horseshoe whip snake Like most snakes in Spain they are harmless just a bit scary when they are trying to get in your window!

It's unlikely to be a whip snake - they are very thin hence the name.

It's most likely a grass snake or a Montpelier. Difficult to tell apart except that the Montpelier is a bit more aggressive - I had an argument with a 2m one a few years ago and it was a bit scary when it rises up and hisses at you from about a metre away.

Some images here

Grass snake http://goo.gl/hrnJs

Montpelier snake http://goo.gl/BUwzN

Montpelliers are very common throughout most of Spain.
Theres quite a few around my way.
They have a poisonous bite but its not normally very serious.

Hi we get lots of the Montpelier snakes in our garden and they do hiss when approached but once you leave them alone they quickly disapear. The dogs bark at them but don´t seem to want to get too close. Our garden is basically a one acre field so I suppose a good place for them.

Although the Montpelier is officially venomous, apparently the position of it's fangs make it very difficult for it to bite you - just a design fault!

However I wouldn't put it to the test!

Firstly, a very big thank you to those who have responded with suggestions, links and photographs. It's very gratifying to be reminded of the enormous capacity to help, pass-on experiences and knowledge that members of this forum are capable of.
Anyway, to the point. It's most definitely a Montpelier snake. I was aware of grass snakes here, but not this type and now having read about it, we don't think we'll be getting too close to it, if we can avoid doing so that is! It's a bit disconcerting to know it's out there lurking somewhere.
One again, thanks to all.

A baby then.

It's back again. Must like it here which is a bit worrying!

It'll keep you mouse and rat free,and as previously mentioned it's back fanged so you have to work very hard to get poisoned.The Lataste Viper http://en.wikipedia.org/wiki/Lataste%27s_viper is the only remotely dangerous snake in Spain.they are difficult to find.They are found in the Sierra Mariola National Park where I have a house and I've only seen 1 in over ten years (and I look for them)

A couple of things to remember...unless you threaten it,surprise it or stand on it, it won't attack. From the snake's point of view, you are several hundred times bigger than it and therefore to big to be food and it's more likely to get dead than you are. If you want it to "hiss off", throw something like a stone near it, but not at it. The vibration will make it want to move off.

Thanks for that. We're not particularly bothered by its presence, but it's always possible that it could be stood on or 'surprised' if it's under a bush for example. Don't fancy the resultant attack!