Do you really mean Snow tyres, or do you mean cold weather or Winter tyres?
Little bit of info about tyres:
It's not the tread pattern that counts so much as the recipe of the rubber used.
Summer and all-year tyres have a rubber compound that below 7°C goes hard and therefore loses grip.
Winter tyres have a compound which remains supple even in extremely low -30°C temps.
This is the fundamental difference between Winter and non-Winter tyres. What it means is the during the colder weather from for example 1 Nov to the end April ie when the weather is going to be colder, Winter tyres give significantly better grip in
ALL conditions.
Now, Winter tyres also have a different style of tread pattern - it's not aggressive like a mud tyre at all, the treads are very fine but lots of 'em.
When will the UK get this, Winter tyres are not just about snow, they're about driving in Winter cold conditions, whatever they may be.
Have a look at the tread patterns here:
Vredestein Tyres / Winter Snow SUV 4x4 / Vredestein Wintrac 4 Xtreme - 235/70 R16 106H TL Fuel Eff.: C Wet Grip: E NoiseClass: 2 Noise: 71dB Winter - Snow - Cold Weather - SUV/4x4 Tyres - 16" R16" - 235/70/16, 235/70R16
Winter tyres are mandatory in most European and Scandinavian countries because they just work.
Dave