Through the first half of the 20th century petrol advertising was commonplace - with the majority of households running petrol cars competition was fierce. As diesel was generally only used in industrial applications and haulage firms tended to purchase their fuel on account, advertising for this type of fuel was less necessary. However around the middle of the century, engine technology was advancing and diesel engines were becoming more refined, they were; quieter, more economical and more efficient. This lead to a rise in the number of small vans and even cars using diesel and with individual 'consumers' now buying diesel the fuel companies started to increase their branding. 
This Esso Diesel, paint on metal, advertising sign is a good size (just shy of a meter square) with simple, clear graphics. The sign is difficult to date accurately as Esso have run this version of their logo from 1934 to the present day. It is produced by Plastemal who's mark is often found on paint on metal signs produced in the 50s and 60s - this example is likely to be from a similar period. 
Condition is generally good - the majority of the sign retains a good shine and the colours remain bright. There is light surface corrosion along the bottom edge, some scratches as well as discolouration towards the outer edges. The sign has an 8mm return that is largely straight, through is split in the upper middle (probably where someone has tried to hang it on a single screw) this isn't really noticeable. 
The sign retains mounting holes in each corner and is easy to fix neatly to the wall. It is 97cm square and around 8mm deep.