Back in September, British carrier O2 teamed up with HTC and started an initiative to reduce the number of unwanted smartphone chargers in the United Kingdom. The carrier estimated that around 70% of handset buyers already had a charger that would be compatible with their new device, and so it started selling certain HTC devices without them.

O2 is now reporting that the initiative has been a big success. 82% of customers didn’t need to purchase a charger with their smartphone, the company claims, which surpasses its initial expectations for the effort.

“More than four-in-five of our smartphone customers who have participated in the trial are willing to buy a new phone from us and to use an existing charging device to attach it to the mains,” said Ronan Dunne, CEO of O2.

“The results of the trial demonstrate a clear willingness among consumers to consider and respond to the environmental argument for taking a phone charger-free. I now hope that as a result of this study the rest of the industry will now consider joining us in our campaign to take chargers out of the box for good.”

Those who did need a charger with their smartphone were able to purchase one “at cost.”

O2 predicts that if its initiative was applied to every smartphone sold in the U.K. during a 12-month period, there would 24 million fewer chargers. According to the company’s research, there are 18,700 tons worth of unused chargers in the U.K. — enough to fill four Olympic swimming pools.

By 2015, all handsets sold by O2 will come without a bundled charger.

• ViaEngadget