Their access to Cloud hotspots will be blocked from this Thursday after the two firms could not agree on an extended hotspot sharing agreement.
BT started sharing hotspot access with The Cloud in 2005. The end of access to Cloud hotspots for BT Openzone customers will mean they now cannot get wireless broadband in 7,500 places in the UK, including airports, railway stations, restaurants and pubs.
They will instead have to rely on getting access in 3,000 BT Openzone UK hotspots. Many customers may now consider paying subscriptions to The Cloud instead, to get wider access.
O2, Orange and iPass and other customers will continue to have access to hotspots run by The Cloud.