This is the second of the most common of the Wrenn R1 Tank Locomotives issued by Wrenn, Basildon over all 4 Periods.Running number on the Tank Locomotive is 31337 in black BR Livery (late crest). The Locomotive is very popular  for "OO Gauge" Layout use on both freight and suburban passenger traffic.Most examples today are "play worn" this is not.

The Locomotive comes complete with Period 3 box, tissue, packing rings, Hornby Dublo coupling conversion kit and single page Instruction Sheet. Based on the box finish this is a mid Period 3, Wrenn, Basildon issue.(circa 1974/5) in my opinion. 

Condition of the Locomotive is " near mint" box is "excellent" for their age.