White flowers (escapees?)

White flowers (escapees?)

Observation - White flowers (escapees?) - UK and Ireland. Description: A group of plants with 6-petalled white flowers with a dark line extending up the tube to the petal tip. Long narrow leaves. Looks like an Ornithogalum but the petals don't really match any pictures I can find. Growing from grassland close to a cliff edge

A group of plants with 6-petalled white flowers with a dark line extending up the tube to the petal tip. Long narrow leaves. Looks like an Ornithogalum but the petals don't really match any pictures I can find. Growing from grassland close to a cliff edge and beside a pavement.