Pesky green stuff

Could it be purslane?
www.ediblewildfood.com/purslane.aspx
We had that in our garden in France, very invasive, but easy to pull up (shallow roots.)

www.rhs.org.uk/advice/profile?PID=498

ThankyouFennel, I looked Purslane up and it's not that,
Thankyou Mimiro for the link , it is Oxalis , the article was very informative with tips on how to get rid of it before it takes over completely , It,s a very active little b----r to get rid of,!! Thanks for your help, i am off to get some weed killer now,

I don't mind the pink variety so much, as the much smaller, bronze(y) type leaf, with yellow flowers that bugs me. Comes up in all cracks and crevices, pesky blighter.

Yes, we have both!
And something in the lawn which has reappeared, like large flat mats with yellow flowers. I don't want to treat the lawn because I am conscious of the wildlife - I don't want birds to eat worms that have been treated with anything.

Lilypops, yours sounds very like aqualegia which self-seeds everywhere and you just have to keep digging it up.

Jalima, I think yours might be crows foot trefoil which is hard to get rid of when in a lawn. If it is that, the bees love it so you are doing your bit for environment by letting it stay.

If the flowers close up when the sun goes in it is oxalis. Useful for filling up odd, doing nothing, spaces. I put some in my rock garden, though, and it is taking over so will have to be culled.

It is oxalis and I spend half my time pulling it up it goes simply everywhere but I can’t get cross co it s a pretty little pink flower. I also have Hawkweed which is so prolific I m constantly pulling that out only to find three more