Charges
Remember that you will be charged for calls you receive when you are abroad - you will pick up the international "leg" of any calls. This may seen unreasonable, but callers may not know you are overseas or not be prepared to pay an international call charge. If you want to avoid being charged in this way, you can set your phone to divert to voicemail and retrieve messages later. Alternatively, some networks offer a service that will divert your calls to an operator at a bureau. Calls are answered with your customised greeting and the message comes to you as a text message.
Before you leave home
Mobile phones normally come with an international call bar in place, so if you haven't already used it abroad, ring your service or network provider to get it lifted before you go. At the same time it is worth asking for the full number of your voicemail box. The short dial number you use in your home country to retrieve voicemail messages will not work in the UK - you need to know the full number including the international dialling code from the UK. For ease of use, programme the full number into the phone's memory, prefixed by the UK international dialling code, and then you won't need to worry about it again.
In flight
Please remember to switch your phone off while on the plane - but if you can't wait until you get there, help is at hand as many airlines now offer satellite phone facilities and with some service providers you can use a Skyphone card, which you just swipe through the slot in your armrest. You will be billed in the usual way on your mobile phone bill.