999 calls are not being connected to police forces and other emergency services because of a technical fault affecting the national system.

Scotland Yard said they were alerted to the issue shortly after 8am on Sunday and have advised London residents to use 101, usually a non-emergency number, as a temporary measure until the problem has been resolved.

It is understood the fault is a “national issue” affecting other forces across the country. The 999 phone line is operated by BT which then routes calls to individual forces.

The Metropolitan Police tweeted: “Due to a technical fault that is impacting a number of police forces, many 999 calls are not connecting.

“Until further notice, please call 101 in an emergency. Please ONLY call in an emergency and please wait until later to make any 101 non-emergency calls.”

Patients in eastern areas of England have also been advised to temporarily call 111 in the event of an emergency.

The East of England Ambulance Service NHS Trust tweeted: “We are aware of an issue affecting the national 999 call system this morning. BT are working to resolve this as soon as possible. In a medical emergency, if you are unable to contact 999, please call 111.”

This story is being updated.