Possibly knautia.

Cynara cardunculus (Cardoon) perhaps?

Looks very like a knautia I've just bought.

In Cardoon, the leaves are alternate, that is, they grow one at a time along the stem. In Knautia, as here, the leaves are opposite, that is, they grow in pairs along the stem.

I would agree Knautia as I have these spring up everywhere, including the paths, having planted a few some years ago. Pretty if in the right place, otherwise they tend to flop and smother other plants.

Thanks everyone