Sonar used to search for body of four-year-old Dylan Cecil

Specialist sonar equipment is being used today to find the body of a four-year-old boy lost at sea.

Dylan Cecil was on holiday with his family when he slipped from the jetty at Burnham-on-Sea, Somerset, at 6pm on Sunday.

His mother, Rachel McCollum, yesterday said he fell into a "whirlpool" and she knew immediately that she would not see him again despite her desperate efforts to save him.

UK underwater rescue organisation SARbot was on the scene last night and is using sonar equipment to scour the water for the boy's body today.

The charity's Twitter feed said they will also use an underwater robot.

The organisation said its sonar equipment is more sensitive than that used by police.

Dylan, from Kettering, Northamptonshire, was visiting his grandparents in nearby Brean with his mother, father Darren Cecil and two younger sisters, aged one and three.

He had wanted to get a closer look at the sea when he slipped off the side of the jetty and disappeared beneath the muddy water.

His parents desperately tried to rescue him, but were unable to reach their son and had to be pulled from the water by passers-by.

A large search and rescue operation was launched by the coastguard and police after a member of the public saw Dylan's parents attempting to rescue him.

The search for Dylan, who was dressed in a T-shirt and shorts, was called off at 4.30pm on Monday but volunteers have continued to look for the boy in order to bring closure to the family.

Ms McCollum told the BBC: "He was literally not even a metre away from me and he was jumping and slipped and I watched him fall in.

"I jumped in straight after him - what more could I do? He went. I knew as soon as I jumped in I was not getting him back."

She thanked everyone who had searched for his body and implored people not to give up looking for her "gorgeous" and "bubbly" little boy.

"I just want my son back," she added.

"He is coming back, he's definitely coming back. I just don't want him to be lost out there and not come back at all."

The waters off Burnham-on-Sea have one of the highest tidal rise and fall ranges in the world and the shoreline is notorious for its dangerous mudflats.

The local authority, Sedgemoor District Council, said that it was satisfied that all its procedures were followed correctly and there are many warning signs along the beach, esplanade and on the jetty hut.

But it said it is also carrying out an internal review "to establish all relevant information".

PA