The O2 Recycle scheme has recycled its two millionth mobile phone.
Since 2009, the programme has handed back over £135 million to consumers who have traded in old mobile phones.
O2 has partnered with phone recyclers Redeem on the programme.
Since its beginning, the iPhone 4S has been the most recycled phone, accounting for 8% of total volume and giving back £15 million to customers.
O2 head of sustainability marketing Mark McGinn said: “When we launched O2 Recycle in 2009, our ambition was to offer people a simple, environmentally friendly way of disposing of their old tech and to reward them for doing so.
“We’re proud to have reached this landmark figure, with more people than ever recycling their devices with us and becoming the biggest mobile network recycler in Europe.”