A special version of the Avro Lancaster was built to enable the trip to Japan carrying an Atomic Bomb -- this version (only 5 aircraft in all) was named the
Avro Atomic. No squadron codes were worn - each aircraft was identified by its individual name.
The fuselage was lengthened to house the extra fuel & the wings extended for added lift, new-type engines were also fitted. Due to the size of the bomb the bombay doors had cut-outs and aerodynamic fairings fore & aft -- these could be jettisoned just before dropping of the Bomb if necessary.

The "Atomic" would become the prototype for the post-war Avro Lincoln.