A technical problem severely disrupted 999 calls to the Scottish Ambulance Service for several hours, it has emerged.

Emergency calls to its three dispatch centres had to be diverted to Northern Ireland and England when a glitch occurred in the telephone system on July 21.

Inverness staff were the first to encounter difficulties at around 1am.

The problem hit Edinburgh at 9.42am and then the Glasgow centre at 9.56am, where a team was able to receive a limited number of calls.

All the centres were fully operational again by 3.30pm.

Labour’s Jackie Baillie said she was made aware of the system failure on a visit to the Northern Ireland Ambulance Service in Belfast on Wednesday.

The ambulance service said it was working with BT to ensure there would be no repeat of the fault.

A spokesman said: “The Scottish Ambulance Service’s contingency plans for this scenario are for calls to be routed to Northern Ireland Ambulance Service and North West Ambulance Service control rooms, who relay information to Inverness, Cardonald and Edinburgh Emergency Medical Dispatch Centres (EMDCs) via an alternative phone system.

“These contingency arrangements were successfully implemented and both Northern Ireland Ambulance Service and North West Ambulance Service passed call information to our EMDCs, who continued to dispatch ambulances to patients in need throughout the course of the BT failure.

“It is reassuring that contingency plans developed for such scenarios worked with the minimum disruption for patients.

“We have reviewed the incident with BT and they have agreed to an action plan to ensure that there is not a repeat of this type of fault.”