Pink Wildflower for ID please

Pink Wildflower for ID please

Observation - Pink Wildflower for ID please - UK and Ireland. Description: This is quite a small one. I am finding it growing on the steps outside of my front door. The flowers of the Ivy-leaved Speedwell that is growing beside it are at least five time bigger than this. I have not been able to see this flower open. It has a squ

This is quite a small one. I am finding it growing on the steps outside of my front door. The flowers of the Ivy-leaved Speedwell that is growing beside it are at least five time bigger than this. I have not been able to see this flower open. It has a square stem and the flowers grow in whorls above a pair of opposite leaves. Not an easy one but thank you for looking- Colin