A company which bombarded mobile phone users with messages promising them a £500 mystery prize, has been fined for a second time by the industry's watchdog.

Leeds-based Mobey Monkey was found to have seriously misled owners with its messaging tactics and fined £50,000.

Customers phone a premium-rate line at a cost of £1.50 a minute, only to find out they had won discount holiday vouchers.

The industry watchdog, Icstis, received more than 200 complaints including some from parents who said their children had been targeted.

Our sanctions against Moby Monkey Ltd reflect the serious consumer harm caused by their service

Icstis director George Kidd

The company, which is now barred from sending out the message, has said it will appeal.

Moby Monkey was fined £6,000 earlier this year for breaches of the Icstis code of practice.

The watchdog's director George Kidd said the company's service caused "serious consumer harm".

"We will not hesitate to take swift action against the small minority of service providers who think that they can abuse public confidence and trust in text messaging in order to make money with no regard for consumers whatsoever," he said.

Holiday vouchers

Mr Kidd added: "Our sanctions against Moby Monkey Ltd reflect the serious consumer harm caused by their service and its promotion, and will act as a warning to the industry."

Calls to the premium rate line lasted three to four minutes.

But the prize turned out to be holiday vouchers with a variety of conditions attached.

One complainant reported receiving the message up to 40 times a day.

A spokesman for Moby Monkey said it would appeal against the decision.