Its liverwort - this grows in shady, damp areas and particularly where the soil is compacted. Easy to remove with a bit of work and hand fork or a garden fork from beds and borders, can be scraped out of cracks between stones, and there are some chemical treatments. Be wary of chemicals though, they can also kill other, non woody plants, so not good for use round your food plants, and make sure products are safe to use on block paving. Link here for more info and advice

https://www.rhs.org.uk/advice/profile?PID=412

Normally not a problem around other plants, though a heavy crust of it can interfere with seed sprouting. The simplest way of dealing with it in garden beds is regular cultivation, though veggie gardens normally have enough sun to discourage invasion by liverworts.

You can keep it in check in the veg plot with regular hoeing as it won't be happy on soft open soil.

Oops sorry Tug, we crossed.

'Sallright!

Thank you all for your help. I'm not too worried about my drive but now I know how to deal with it among my veggies