I've noticed for a while, big packs of brushes and sponges in different shapes and sizes in the children's hobbies section of W.H. Smiths. Those sort of funny, stiff brushes used for gluing.
There aren't many shops open at the moment, and these packets were going down pretty quickly. Obviously, lots of people are doing more arts and crafts at the moment.
Although not needed for my current painting, I finally succumbed and bought a set before they had all gone.
Sometime I want to do some free marking making experiments (I already have a set of wire brushes) for a picture were chaos is an important feature. Dots, dashes, scratchy lines etc. are just what I'm looking for.