This tray was made by the London company KAYMET in the 1960's. The company still produces trays to this day, but not in this style.
made from anodised aluminium, it has an unusual machined texture on the base, most are just a plain pattern.
this is the largest tray and measures 61cm handle to handle & 37.5cm wide
it also has a dark blemish on the top, but its age related and doesn't take from the product.