Mobile phone and landline coverage was lost for several hours this afternoon resulting in disruption across Shetland and Orkney and affecting thousands of customers.
The Gilbert Bain Hospital lost its landline for a number of hours and flights at Sumburgh were delayed or cancelled.
Some services were restored by 5pm, though there were still people without a mobile phone signal after 6pm.
Sumburgh Airport closed at lunchtime due to the phone line problem affecting radar communications.
As a result, four inbound and seven outbound flights were cancelled and one was diverted to Kirkwall.
Highlands and Islands Airports Limited said it will not re-open until lines are fully operational.
HIAL advised passengers to contact their airlines for more information.
BT said at around 1pm today it experienced problems at Wideford Hill radio station in Orkney which affected services in Orkney and Shetland.
It said: “National Air Traffic circuits and coastguard circuits were also affected, forcing the closure of Sumburgh Airport when their radar systems failed.
“Emergency services also went down in parts of Orkney and Shetland.
“Engineers traced the fault to blown rectifiers and fuses at the radio station and restored service around five hours later when all the blown equipment was replaced.”
Around 390 customers lost broadband while 2,640 lost telephone lines.
BT apologised for the problem which they said is under investigation.