The Advertising Standards Authority (ASA) has chastised O2 over a misleading advert revolving around iPhone 5 delivery dates.

In its website's Frequently Asked Questions section, the mobile operator stated, "If we get your pre-order before 4pm the day before launch, we'll get [the iPhone 5] to you the next day."

Six customers filed objections with the advertising regulator, five of whom failed to receive their Apple devices on launch day. All six complainants identified O2's claim as misleading.

O2 opposed the charges, saying that these customers had confused pre-orders with standard orders. The network explained it stopped accepting the pre-orders as soon as initial stock had been exhausted, replacing them with standard orders, which in contrast could require up to three weeks to be dispatched. "Those making a standard order...should have been informed that the product could take up to three weeks to be dispatched," O2 said.

However, the watchdog has upheld the complaints, ruling, "we did not consider that the claim "If we get your pre-order before 4pm the day before launch, we'll get it to you on launch day" made that distinction clear to readers, who would instead infer that all iPhone 5 orders placed prior to 4pm the day before launch would be delivered on launch day."

The ASA has ordered that the claim must not again appear in its current form and that the distinction between pre-orders and standard orders must be clarified.

"We accept the ASA's ruling and apologise to those customers who were led to believe they would get an iPhone 5 the next day as a result," responded an O2 spokesperson. "We can confirm that the claim will not appear again in its current form, and we will ensure that our ads make clear the distinction between 'Pre-Orders' and 'Standard Orders' in future."