Lebara Mobile - good SIM card for visitors to the UK

I picked up a Lebara Mobile SIM card the other day for a fiver. Free SIM with £5 of credit on it. Useful for testing and to use in an emergency handset. Lebara offers international calls from 4p per minute & UK calls at 10p per minute. Worldwide SMS charge is 10p per message.

Struck me this could be a good option for visitors to the UK who will need to phone home and don't mind swapping their SIM card.

• EU destinations are 4p per minute to landlines with mobile rates around 15p per minute
  
• USA is 5p per minute to both
  
• Canada is 4p per minute to both
  
• Australia is 4p per minute to landlines and 15p per minute to mobiles