O2's chief executive has admitted that his company's data network has been unable to keep up with the "explosion" in popularity of the iPhone.

The mobile operator's London data network has suffered a spate of crashes over the past year, as it was hit with unprecedented demand from data-hungry smartphone customers.

The success of smartphones, led by the iPhone - which was available exclusively on O2 until November 2009 - has caused an 18-fold increase in data traffic since the beginning of 2009, according to the company.

O2 also claimed that data traffic across all UK networks is doubling every four months. However, the company claims it's better prepared for the future after investing £30 million on its London network, which includes the creation of 200 extra mobile base stations.

"Where we haven't met our own high standards then there's no question, we apologise to customers for that fact," O2 chief executive Ronan Dunne told the Financial Times.

"But it would be wrong to say O2 has failed its customers en masse."