From the NATS website:
Statement on Icelandic volcanic eruption: Friday April 16, 2045
The volcanic ash cloud continues to affect UK airspace. Following the latest update from the Met Office, NATS advises that the restrictions currently in place across UK controlled airspace will remain in place until at least 1300 (UK time) on Saturday April 17.
There are currently no airspace restrictions in Scotland, Northern Ireland and in an area over the North Sea that includes the Shetlands and Orkney Isles. Manchester, Liverpool and all airports North of those may be available from 0400 (UK time) – 1000 (UK time) for departures to and arrivals from the North and West subject to individual co-ordination. However, please be advised that the situation is continuously changing. Forecasts indicate that the ash cloud is expected to return over Northern England at 1000 (UK time) and it is likely that restrictions will be reintroduced.
Please note these arrangements do not mean that all flights will operate. Anyone hoping to travel today or tomorrow should contact their airline before going to the airport.
We are looking for opportunities when the ash cloud moves sufficiently for us to enable some flights to operate under individual coordination with ATC.
We will review further Met Office information and at 0900 (UK time) on Saturday we will advise further arrangements.
We continue to work closely with airports, airlines, and the rest of Europe to understand and mitigate the implications of the volcanic eruption.