Originally Posted by Heathrow Tower

Not a pilot, but the approach angle is 3 degrees below the horizontal (this may feel different, as the aircraft will be nose-up to the airflow (called angle of attack or AoA)).
Departure is usually between 10-15 degrees initially.

Just seen Waterhorse's post, layman v expert(!!)

OP, did you mean mandated minimum gradients, or what actually happens? (as they can be quite different).