A man was jailed for 30 months yesterday for his part in a multi-million pound fraud in which mobile phone SIM cards were altered to enable users to make unlimited phone calls.

Electronics engineer Radomir Lukic, 41, of Loughborough, Leicestershire, had earlier pleaded guilty to defrauding BT Cellnet and Telewest of an estimated £3m. It is believed to be the largest conspiracy of its kind in the UK to date.

Leicester Crown Court heard that Lukic sold decoders that allowed free and illegal access to cable TV networks and was also involved in the sale of pirated CD computer games.

Lukic was involved in the "chipping" of certain free-paid phones used on the BT Cellnet network, and the manufacture and distribution of unauthorised decoder devices, sometimes called "Baby J's". These boxes allow users to receive analogue cable channels without making payment. In addition to this he sold modified phones for up to £250 on the black market.

The fraud came to light at the end of a two-month undercover operation, code-named Mantra, which was led by the Rugby Branch of the National Crime Squad and grew to include fraud investigators from BT and Telewest.

After Lukic's arrest in November 1999, searches were carried out on his home address and a purpose made factory which recovered 200 pre-pay mobile phones and 400 electronic cube devices that provide unauthorised access to cable TV channels. A large amount of computer hardware and software, and almost £22,000 in cash was also recovered. ®