Flower ID please

This plant is self sown this year (and last) from seeds I planted two years ago, from either a packet of "cottage garden annuals" or wildflowers. I rather like it, but can't ID it. From memory it seems a less deep pink now than in the first season, but this is likely two generations of seed later.

Flower close up:


Showing more of the plant. Very upright stems, with flowers forming at intervals around the stem and blooming from the bottom up:



thanks!