Charge Networks in the UK and Europe

Can anyone in the UK recommend a charge network that I can join to charge while out and about?

So far I have only charged at home.

I tried searching on my mobile phone but it came up with a large number of app suggestions. I tried the first two and neither seem to cover the UK. Rather than install and unistall a load of Apps what do you recommend? Ideally a free network that charges when I use it and not when I don't.

I intend to travel in europe in the summer so another suggestion that covers France, Belgium and Holland would be good too.

Kevin