Purple flower found on verge?

Purple flower found on verge?

Observation - Purple flower found on verge? - UK and Ireland. Description: Heart shaped hairy leaves with serrated edges. Stiffly haired stem. Leaves opposite. Purple clustered flower with 4 petals.

Heart shaped hairy leaves with serrated edges. Stiffly haired stem. Leaves opposite. Purple clustered flower with 4 petals.