The critters are harmless but irritating as they can often entirely cover a surface when they land in large clusters.
They’re pollen beetles, and their population expands during periods of warm weather.
They are attracted to bright colours, which explains why they may have been paying particular attention to your clothing.
Pollen beetles are typically common near rape seed fields, and as their name suggests, they feed on pollen.
They can’t harm humans, animals or garden plants and there is no effective means of controlling their numbers.
So if you see them swarming your washing line, there isn’t much you can do other than shake them off!