Copied this from the NTLWorld website:
As part of the ongoing project to maintain and upgrade our Broadband network, there is a requirement to carry out maintenance and upgrades on components which may result in a loss of service for the duration.
The week commencing Monday 9th October
On the morning of Tuesday 10th October between midnight and 6 AM,
Network optimisation will result in a brief loss of service in the Luton, Stoke, Fareham, Poole, Brighton and Waltham Park and surrounding areas.
Network updates will result in a brief loss of service in Grimsby, Shepshed, Colchester, Leicester, Swansea and surrounding areas.
Network upgrades across the country will result in a brief loss of service for all customers.
On the morning of Wednesday 11th October between midnight and 6 AM,
Network optimisation will result in a brief loss of service in the Barnet, Luton, Charminster, Cosham, Stoke, Southampton and surrounding areas.
Network updates will result in a brief loss of service in Grimsby, Shepshed, Woking and surrounding areas.
On the morning of Thursday 12th October between midnight and 6 AM,
Network optimisation will result in a brief loss of service in the Leicester, Renfrew and surrounding areas.
Network updates will result in a brief loss of service in Grimsby, Northfield, Guilford, Paisley, Bishopbriggs and surrounding areas.
We apologise for any inconvenience that these planned works may cause.