Of course it depends on time of day, traffic conditions and weather. I have heard people have done it in 1 hour 20 minutes. I think you should allow 2 1/2 hours depending on where in London you are traveling from.
About 3 hours by car.
Birmingham to the outskirts of Berkshire. About an hour by car
It takes around two hours by car to get from Hereford to Birmingham
About five hours.
3 hours
To get to Aberdeen from Birmingham it would take roughly 7 hours by car or an hour and a half by plane.
a long time
Depending on traffic and weather conditions, driving from Oxford to Birmingham will take about an hour and 20 minutes if you take the M40.
About 2 hours by car & 3 by train.
About 45 minutes on the bus and 20 by car
14 hours
about an hour