The system is based on the JT Travel SIM, which is on sale for £2.99 and is compatible with most mobile phones now on the market.

The product enables users to make international calls for 25p upwards, to send texts for 25p and to transfer data for 50p per Mb.

All incoming calls to a customer’s JT phone are free and the service is available on some 430 networks in over 200 countries.