This is an excellent example of the Wrenn W4626 "Blue Circle" Cement Wagon in Grey, issued in the late Triang/Wrenn (P2) era. This has the Yellow "Blue Circle" board and round blue motif. 

This is recognised as late issue by the "metal rimmed" wheels and pin wheel axles. Earlier versions had the plastic wheels as Period 1. Basildon issues.

Comes complete with Triang/Wrenn box and yellow plastic insert

Overall Condition is "near mint" for their age.