Thousands of O2 customers in south London have reported problems of using data and 4G services.

Several users took to Twitter to complain about difficulties connecting to the network, which were first reported at 5:30 am.

The outage is also having knock-on effects for other services that rely on the O2 network, including Transport for London's electronic timetable service at bus stops, which has stopped working.

O2 is the second-largest mobile network in the country, behind EE.

It has 25 million direct customers, but also provides services for the Sky, Tesco, Giffgaff and Lycamobile networks.

Once those are taken into account, up to 32 million customers across the UK are affected.

One O2 customer, who had a double lung transplant five months ago, contacted told the Wandsworth Times that she is "currently waiting for hospital transport to collect me, they are late and I have no way of calling them or my hospital with O2 down.

"At this early stage it is important I get to these clinics and keep in contact with my specialist team. Im at a loss and now so stressed out."

On Twitter O2 said: "We are aware our customers are unable to use data this morning. Our technical teams are working on the issue with high priority. We are really sorry and working as hard and as fast as we can to fix this."

Are you an 02 customer who has been affected by loss of data? Tell us about your experiences by emailing or calling 020 8722 6310.