Bus lanes, ambulances and ordinary drivers

[YogaLite]

Can/should ambulances use bus lanes?

I was driving in a 3 lane town street in slow traffic, the near side lane was a bus lane.

Ambulance kept trying to squeeze b/w the 2 other lanes expecting middle lane drivers to go into the bus lane but not everyone did.

I am sure I have read somewhere that people get fines for being in a bus lane but not sure how easy it is to argue out of them.

Surely ambulances or other emergency services should be allowed to use bus lanes? Are they allowed to not, does anyone know?

In London, we are allowed to use bus lanes, mainly on lights but there are other exceptions for us too.

Local knowledge is key - a lot of bus lanes end onto 1 or 2 lanes of traffic, which impedes progress to an emergency call or hospital.
Moving other vehicular traffic to the left is to our advantage.
If you find yourself with a lane fine then there will likely be photographic evidence of such.

Thank you @AlphaAlpha
This was one of the London suburbs but not a London borough.
The bus lane was empty and all 3 lanes continued to the roundabout where there are traffic lights. Seemed obvious for the ambulance to use the empty bus lane so I was surprised it didn't.

PS. Hats off to you for doing that job, driving as well as dealing with emergencies.