The ordinary tyres when compared to winter tyres fail in situations where the car is held up in a driveway filled with snow. Winter tyres on the other hand transform the car and make them usable even in extreme conditions such as sleet, rain, snow, dry, slush, up hill and down dale.
One should never take liberties with the functioning of tyres. While driving on black ice the safety is of utmost importance and since in UK it almost snows for the most part of the year the need for finding a winter tyre increases even more. Taking this fact into consideration the tyre manufacturers in UK have started making extra tyres but over the past few years the demand has far exceeded the supply.