what does it mean: "Do these turn-ups work with these boots?"

Question

I have been watching a funny British show (Catherine tate) about a gay boy coming out to his mom. The reactions from mom and neighbors are funny.

But at the end of it, there comes a scene where 3 thugs come to the boy's house and the boy opens the door with mom behind him. one of the 3 guy's showing his boots says:

"...Do these turn-ups work with these boots..."

It must be funny as there comes the laughter track, but I did not understand what it means. Can you tell me what it means and why it is funny?

Thanks

Here is the video where the sentence context starts (minute-seconds 4:40:: https://www.youtube.com/watch?v=_mflUTy6v6M

Answer 1

A turn-up is a fold at the bottom of the trouser leg. You turn the bottom of the cloth up to make the length shorter. You can see the three guys all have turn-ups in their jeans.

The joke is the contrast in expectation. We expect the three guys to be aggressive thugs, but actually, they only want fashion advice. This is an example of "bathos".

You may have noticed the accent. This is a Northern Irish accent. The North of Ireland is a socially conservative part of the British Isles. Even now, it is the only part of the UK which doesn't have marriage equality. Setting the sketch here increases the comic contrast.