Two children have died in recent days as a result of being washed out to sea while on holiday, the first on the Somerset coast and the second in Portugal.
Brighton Coastguard manager Graham Easton explains here how you can stay safe on the beach.
Most importantly, he advises to only enter the water between the red and yellow flags which signify that a beach is supervised by lifeguards. He also advises against going in after someone who is in trouble.
Colleagues of the father whose five-year-old daughter and father-in-law were washed out to sea in Portugal are said to be "totally shocked".
Professor Phillip Lewis has taught at the geography department of the University College London for 24 years. His page on the department website says his research is concerned with"monitoring vegetation using Earth Observation methods".
One of his colleagues in the department said : "I had no idea his daughter was the little girl involved in this tragedy.
"Everyone here will be totally shocked. My heart goes out to him and his family at this sad time."
A spokesman for the Maritime Authority in Nazare, Portugal said the part of the beach where the incident happened is widely known in the area to be hazardous. He said:
"The sea in that beach is very dangerous. The wave that swept them in was very big.
"The beach has information that tells you about that area where they were and it tells you there's no surveillance, no lifeguards, on that part of the beach. It's very far from where they are stationed."
Jorge Barroso, the mayor of Nazare municipality where five-year-old Lara Lewis and her grandfather drowned, has called the tragedy a "regrettable accident". He added:
– Jorge Barroso, mayor of Nazare municipality
The accident happened on a beach with a sea considered very dangerous and in an area without surveillance. The municipality of Nazare advises tourists and visitors who are willing to enjoy our coast, to go to safeguarded beaches, and always respect the safety rules and directions given by lifeguards.
66-year-old Brian O'Dwyer was already dead when he was pulled from the sea along with his granddaughter Lara Lewis and wife Jill, according to local rescue services on the Port of Nazare in Portugal.
The trio were taking a walk along the Salgado beach yesterday when 5-year-old Lara was swept into the sea, both grandparents attempted unsuccessfully to rescue the little girl.
Jill O'Dwyer is said to be recovering in hospital. Last night a neighbour of the family said Brian was a "lovely man."
The headteacher of Rushmore Primary School in Hackney, London, said he was devastated by the news that 5-year-old Lara Lewis was killed off the coast of Portugal yesterday. Ian Mullaney said:
"We are devastated to hear the news about Lara. She was a delightful young girl from a lovely family and this has come as a huge shock to the whole Rushmore community.
Lara was a bright, friendly and positive girl who was well liked by her teachers and classmates. It is a tragedy and the news is just sinking in for all of us."
Colleagues of Philip Lewis, whose daughter Lara died along with her grandfather after being swept off the coast of Nazare in Portugal, have offered their condolences to the family.
– Professor Jon French, head of Department of Geography
All of us at UCL are deeply saddened to learn of the tragic drowning yesterday, in Portugal, of Lara Lewis, daughter of Philip Lewis, professor of remote sensing in the Department of Geography.
The loss of Lara and of her grandfather, who was also drowned in this same incident, is a truly heartbreaking tragedy and our deepest condolences go to Professor Lewis and his family.
David Mason has lived next to the Lewis family in Hackney for five years. He said five-year-old Lara was an "absolutely charming little child" and that all of the neighbuors will be absolutely devastated to hear about her death.
Five-year-old Lara Lewis died alongside her grandfather, named as Brian O'Dwyer, at the Salgado beach in Nazare in central Portugal yesterday.
The girl's parents, who live in London, Philip and Sian Lewis are said to be in a state of shock.
The girl's grandmother Jill O'Dwyer, was rescued by fishermen and is being treated at the nearby Alcobaça Hospital.