The UK's prime minister has issued a warning after a "real terrible family tragedy". A father, his partner and teenage daughter died after entering the water off Shoreham, in England, on Tuesday. Sussex Police have named the three family members who died in the incident as Hassan El-Khawas, 55, his partner Zeina Alayn, 37, and their 14-year-old daughter, Sara El-Khawas. Another relation, a young girl, remains in critical condition in hospital. Tap the link @BBCNews's bio to read what is known about the incident. #Shoreham #BBCNews