They don't usually chase stolen cars in the UK, high speed persuits are very very rare. They figured the cost to lives wasn't worth the risk. So instead what they do is low profile persuits, and they generally pick up the criminals once they've gotten bored of the joy ride.

Plus they figured a lot of the time people were stealing the cars specifically to have the thrill of the police chase. So by not doing the high speed persuit, they actually cut the numbers of cars being stolen.