A woman and her 15-year-old daughter who died after getting into difficulty in the water on the Essex coast were trying to help a seven-year-old boy, police have said. The child remains in a critical condition in hospital after the incident at West Mersea, near Colchester, on Wednesday evening. Shelina's brother-in-law Matiur Rahman said the family was enjoying a seaside holiday when a "big wave came and took them". "My whole family, we are, like, speechless," said Matiur Rahman, who lives in Bradford, but spoke to the BBC from Bangladesh. Prime Minister Andy Burnham, speaking on a visit to Harlow in Essex, described the deaths as "very sad" and thanked emergency services for their efforts.