Rakisons Solicitors has launched a custom-made phonecard in what is thought to be a world first for a law firm.
Senior telecommunications lawyer Danny Preiskel said around 1,000 of the cards would be given to valued IT and telecommunications clients.
Each card will have around £3.50 of initial credit on it and will be useable around the world. All calls that are less than 30 seconds will be free.
Preiskel, whose department accounts for around a quarter of the firm's work, admitted that the promotion, which he developed with one of his clients, was expensive. But he said he was confident the marketing exercise would be worthwhile.
"We're the first in the world to do this, and hopefully we'll get some benefit from that.
Preiskel said the firm would monitor the use of the phonecards closely to gauge client reaction, but was confident the idea would be adopted by other solicitors firms and professionals.