This is a superb example of the RARE  Wrenn W.5104 "Bulk Flour" 4 Wheeled Tank Wagon in White, running number No 20.  This was the only wagon that Wrenn produced in white self coloured plastic.It does of course have a metal chassis and metal rimmed wheels. On many of the examples seen the white plastic has "yellowed" due to age and layout use, this is not one of these.

Introduced by Wrenn, Basildon in late Period 4 (from 1990), only 187 of these were ever produced. Please note; many have been seen in the "curly R " type W7304 copy  boxes, these were not issued by Wrenn, Basildon please avoid.

The Wagon comes in a correctly stamped Period 4 (type W7304) box with yellow cardboard  insert.

Condition of the Tank/box is "near mint to mint" for their age.