An advert by Vodafone has been banned by the Advertising Watchdog following complaints from rival Telefonica that the ad misleadingly implied that 77% of the emergency services employees used the mobile operator’s service away from work.

The TV ad, by Grey London, had shown a firefighter’s wife leaving a voicemail before a statement from the mobile operator said: "We are honoured 77% of the emergency services uses Vodafone."

Telefonica complained that Vodafone had falsely suggested that the majority of the emergency services staff, including police, doctors and nurses, used Vodafone in their personal – not professional – lives, and that the basis of the claim was unclear.

The Advertising Standard Authority (ASA) ruled that a voicemail from a fireman’s wife is likely to be sent using a personal phone, as opposed to a phone provided by an employer.

It added: ‘We told Vodafone to ensure they did not misleadingly state or imply that 77% of emergency services employees used Vodafone in a personal capacity and made the basis of their claims clearer in future,’

Vodafone said it used data from market intelligence firm Kable to create a clear definition of emergency services. It then calculated from its billing system that it had charged 77% of the workers for a range of services.

The ASA said the ad must not appear again in its current form.