During the mid-twentieth century, no boy's toy collection would have been complete without a Dinky car.
Back then, children had fewer toys available, so such objects would have been highly coveted and cherished.
Presumably to discourage light-fingered rascals, the young McRae scratched his name firmly into the undercarriage of his prized Humber Hawk.
Perhaps you know P McRae's story?
It's not hard to imagine the young lad having hours of fun playing with his Dinky car, perhaps racing it against friends' vehicles down the steepest footpath they could find. Maybe it was part of an impressive collection?