I would greatly appreciate any thoughts on the id of this plant. Found growing on a side-walk this week in Bedfordshire UK. The flower diameter is approximately 1 cm. Given its habitat I believe that it could be an imported rockery plant and one (unconfirmed) suggestion is that it could be a Pratia from New Zealand. Many thanks for your suggestions.
I know this as Bacopa...now apparently called Sutera cordata White, or even more recently Chaenostoma cordatum bacopa white - Google Search sutera cordata white - Google Search Chaenostoma cordatum - Google Search Often sold in spring by garden centres as a trailing plant for hanging baskets.
Spot on SS, many thanks (again!). Your id suggests to me that it had produced seed which had fallen from a hanging basket to the ground and found enough sustenance and moisture to germinate and develop. Not a mean feat in the dry summer that we have had!