The speed limit on most of Britains roads is set to 30mph For a good reason. if you hit a pedestrian at 30mph there is an 80% chance they will live, at 40mph there is an 80% chance they will die.
Driving too fast can cause death to yourself and other road users, you will have to live with the emotional trauma for the rest of your life, you could also face a jail sentence, a driving ban and a fine.
here are some things to keep in mind
Going at speed around a sharp bend could result in you losing control always slow down when approaching a bend or making a turn.
Take Driving conditions into account, if the ground is icy stopping distances will be increased meaning you need to allow more space and time for braking, Equally during poor visibility you should lower your speed.
The speed limit is the Maximum speed you're allowed to go, not the suggested.
Plan journeys with plenty of time so you do not need to speed.
Going at a faster speed means you will have less time to react to a road hazard.
Finally consider the human and emotional cost of killing or seriously injuring another fellow human being just because you were in a rush to get somewhere.