The emergency 999 number is down for some people in parts of the UK, according to several reports.
Cambridgeshire and Suffolk are understood to be affected with people unable to make calls to police, ambulance or fire brigade on the emergency line.
Cambridgeshire fire and rescue tweeted that phone lines were down in the south east of the county. They advised that the public should call 101, the non-emergency number for police, instead.
Suffolk Police advised that calls from mobiles should not be affected.
"Suffolk Police have been advised there is currently disruption to the public 999 service for callers in the Bury St Edmunds and Haverhill area. BT have advised that call from landlines with prefixes 01284 74 or 01440 71 may be disrupted until around 2.30pm this afternoon" it said in a Facebook post.
Both organisations said BT was working to resolve the issue.