Nomi Mobile UK
 

Anyone tried this one. Rates are very low 5p/min in England and 5p/min long distance to call Canada. Sim cards from Telestial.

Not used them personally, but I know people who have their SIMs. They've been around for a while and there's some discussion here on the forum at: http://www.prepaidgsm.net/forum/euro...ls-merged.html

They do much of the worlds landlines at 4 or 5 pence/min, and I think they recently added UK into that too. (...Remember the UK is not just England BLC ;) )
However, UK mobile is higher at 10p/min.

I suppose 10p/min UK mobile is a cheap rate as compared to other pay as you go packages

I'am paying 20p/min with Vodafone UK and their long distance rate is .79p/min.

I think I'll order one of there sims and give it a try next time we are in England.
To bad they haven't fixed the problems with topping up with a non UK credit card!

I don't know what you define as long distance, but calling Canada can be as little as 3p/min on a cheap prepaid card from T-Mobile, Orange or 3. See:
Cheap international calls to Canada

Don't you still have to pay the local call? 20p a minute on Vodafone

Orange Camel is 6-7p all in to Canada. My Call Abroad SIM was 5p when I was in the UK a couple of years ago - a pound bought me 20 minutes of calling home.

Then why am I with Vodafone! Ordering a new sim today!

Vodafone also has an option to drop its rates to 5p, as petkow mentioned

International Calling - Vodafone

Using the Yourcallworld service via the short code access from those operators costs just the relevant tariff, taken from the SIM's own balance

No, on the networks I mentioned you just pay 3p/min, taken from the balance as Andy mentioned! This is by far the best deal available on a prepay in the UK.

For heavy users, remember that Three still allows free Skypeing on prepaid SIM's.