I use two:
www.Webhosting.uk.com
www.eukhost.com
Both have live chat for support 24 hours a day and decent up time.
Price is more expensive than the US counterparts, but just ok for the UK.
I've used them for 8 months and one site was down for 5 hours. They responded to all my emails, and got the site back up quickly. Just the fact that they respond via live chat gives me a more secure feeling.
I'd be interested in hearing others experiences.