Putting on a “spread” is to cook and serve a sumptuous meal.
A tail-gate is the fold-down door on the back of a pick-up truck.
Here, a tail-gate spread (whatever that means in the UK) is to serve a meal, in the parking lot of the
sports stadium, from the back of one’s pick-up truck, either before or after watching the game.
A tail-gate party is when a bunch of friends park in the same area and share their food on their trucks’
tailgates.
Tail-gate spread...think Wookie butt. LOL!