O2 estimated there were 100 million unused chargers in Britain and encouraged competitors to take similar steps so all phones are eventually sold chargerless.

Handset makers promised a standard charger suitable for all smartphones under pressure from the European Commission in 2009, meaning customers who purchased handsets recently do not need a new one for handsets from a different brand.

The European Commission cited environmental concerns and O2 said the number of unused handsets in Britain had already had a "huge environmental cost".

O2 and Taiwanese handset maker HTC launched a trial in October offering customers the option to buy a phone with or without a charger. 82 percent of customers opted to buy a phone charger-free.

Customers who want a charger with their new handset will be able to buy one at cost price, O2 said.