Listed building!!!

Recently I blipped this phone box, I had a closer look at it today and realised that it's a listed building!

I belong to a Health Club called The Lensbury built by Shell Oil originally which is where it is.

Inside it reads
This Post office Telephone Box is one of the few original Type K2 Kiosks circa 1930 designed by Sir Giles Scott.
Kiosks of this vintage are now listed buildings.
This box stood in the courtyard of Shell Mex House in the Strand and this year was officially presented by British telecom to Shell UK Ltd who in turn have now presented it to the Lensbury Club June 1988

It also says
EMERGENCY CALLS
DO NOT INSERT ANY COINS
Lift receiver and listen for dialling tone (a purring sound)
DIAL 0

Ask exchange for
FIRE, POLICE or Ambulance
This telephone is at....

For directory enquiry, do not insert money, dial x0x
For other calls or for assistance do not insert money, dial 100

The Illustration reads
BE PREPARED
BE THRIFTY
It advertises Post Office savings

I LOVE this Phone Box and long to get a closer look, it's in an area of fenced off river bank.......