This is an excellent example of the Wrenn W2223 "Windsor Castle" in BR Blue, running number 4082.  Introduced by Basildon in Period 3, this continued in production into early Period 4. It is claimed that just over 3000 were issued, however based on my experience as a collector I believe the figure is less. This particular example was produced in early Period 3 (circa 1972/3), and is not badly "play worn" like many of its counterparts from this era. Has seen minimal layout use in my opinion, and is probably the best example I have seen over the years from this early Period 3 era.. 

This was the only Castle Class Locomotive that Basildon produced in BR blue, and is very popular for passenger operations on "OO Gauge" Layouts. The tender has the early BR crest, and as with all Period 3/4 Castle Locomotives it has "metal rimmed" wheels throughout, and is powered by the standard high performance ring field motor. 

The Locomotive/tender comes complete with original  box , tissue, packing rings, Hornby Dublo coupling conversion kit and Instruction Manual. The underneath of the inner box is stamped "Packer No 3" in black ink and has the usual sellotape residue marks denoting  Basildon Period 3 issue. . 

Condition of the Locomotive/Tender/box is " near mint" considering their age..