10.30 am: Update 

The Voice and Data Service issue, caused by an equipment failure at a Luton exchange, has been resolved. All services are now working normally.

9.45 am:

We are aware of a service issue with Voice and Data Services, including Leased Line, Broadband and Fibre. Engineers are working on a solution. 

This problem is at supplier level and is affecting around 7,000 customers in London. 

A number of engineers have been allocated to investigate the cause of the fault, at this stage the cause of the fault remains unknown but is being treated as high priority.