Not required at any uni, but may not be favourable by English unis as a 3rd subject as it is SO similar to AH maths and physics...
I started it but never wasted my time on it. At the end of the day, it is another AH, but virtually everything is covered in maths and physics. Would also be very easy to self teach if you really wanted alongside maths and phys. Also, physics has an entire unit on mechanics, and the pure maths section of the applied paper is what is learned in pure maths.