Tridents can reach mach 19. Orbital velocity is more like mach 100.
Not that the UK manufactures trident missiles anyway.
27720km/h orbital velocity is Mach 22.4 at a sea level speed of sound
Orbital velocity is nowhere near mach 100.
if only you could put some sort of explosive charge on the top
You don't need orbital velocity to blow satellites away. Just do a well-timed suborbital launch against the satellite's orbit, and the satellite will provide most of the kinetic energy.