Good question - teach me to shoot my mouth off..
My understanding is that it's illegal to drive with anything on your tyres that will damage the road. That means in practice that you can use snow chains to get from say home/work onto a gritted road but - once you're on a cleared road - you have to stop and take them off as they'll chew the road up.
My daughter's partner is a regular skier and has a set of chains for his trips to The Alps. In the UK, he uses them to get up the hill, out of our village and on to the main road but then stops and takes em off. Where there's snow, the chains do no harm to the tarmac.
That's all I've got
The AA or RAC websites might help or The Dept of Transport website
