Free phone calls from Italy to UK

Since today, I always used Skype to call landline and mobile phones in the UK: it is much cheaper than any Italian telephone company. But from today, I'm going with something else: VoipWiseand VoipBuster. Here is a comparison of the rates to call the UK:

• Skype
  • landline: 0.020 eur/min
  • mobile: 0.236 eur/min
• VoipWise
  • landline: FREE
  • mobile: 0.100 eur/min
• VoipBuster
  • landline: 0.010 eur/min
  • mobile: 0.180 eur/min

VoipWise is the winner!!! Now I can call UK for free! I wonder how long it will last…