Near the end, whilst kneeling, Father Brown recites the Hail Mary in Latin. After saying Ave Maria at the start of the prayer he should say 'gratia' plena, but replaces gratia with what sounds like 'in sancta'. Then, after saying Dominus tecum, he gets the start of the next two lines wrong (transposing benedicta and benedictus). Father Brown should know the Hail Mary in Latin like the back of his hand.