Satellite broadcaster British Sky Broadcasting (Sky) has been told not to repeat adverts claiming it treats new and existing customers alike, after complaints from five people were upheld by the Advertising Standards Authority (ASA).

"Why do existing Virgin Media customers often pay more than new ones?" Sky's adverts in the UK national and regional press said.

"At Sky we think it's wrong to advertise attractive sounding prices that are often only available to new customers, not loyal ones."

However, five existing Sky customers complained that new subscribers often got a better deal than they did.

One Sky customer was told it would cost £159 to upgrade her package to Sky+ compared with £49 for new subscribers, while another was told to pay £45 for the Sky+ box and a £40 connection fee – even though new customers only paid for connection.

Meanwhile, others complained that the offer of a free Sky+ box and free installation only applied to new customers.

In response, Sky said new and existing customers paid the same standard prices for their subscription services and digital satellite equipment.

"Sky explained that standard prices should be seen as distinct from special offers they ran periodically for time-limited periods," the ASA ruling said.

"They said they did not include their special offers in the comparison claim made in the ad."

The ASA upheld the complaints because some of Sky's special offers could not be claimed by existing customers.

"Because existing Sky customers were not able to take part in some offers, we considered that that contradicted the claim 'we think it's wrong to advertise attractive sounding prices that are often only available to new customers'," the ASA ruling said.

"We were also concerned to note that, while Sky did not include their special offers in the comparison, they had included special offers made by Virgin Media to new customers, including some that were time limited."

The ASA found that the ad breached the CAP Code on substantiation, truthfulness, prices and comparisons.