13 February 2012 BBC News updated at 16:35 ET

Firefighters have said an Essex man who stripped to his underwear and crawled across thin ice to rescue his dog is lucky to be alive. Sunday's rescue on the River Stour at Dedham, near Colchester, was captured on camera by a passer-by. It has led to fresh safety warnings to dog owners not to go into freezing water after their pets.

A man who stripped down to his underwear and crawled across a frozen river to rescue his trapped dog has been condemned by firefighters.

According to an eyewitness, the man fell into the River Stour, in Dedham, Essex, at about 10:00 GMT on Sunday but managed to climb out with the animal.

Fellow dog walker Paul Wenborne, who witnessed the incident, described it as a "foolish act of bravery".

An Essex Fire Service spokesman said: "This was extremely dangerous."

Fish porter Mr Wenborne, 52, of Rayleigh, Essex, said he was amazed at the man's actions.

'Stripped down'

"I was with two friends and we couldn't believe what we were seeing," he said.

"He stripped down to his pants and started crawling across the ice.

"About a yard or so from the dog, he fell in but managed to get hold of the dog and put it on the ice.

"He then had to swim two or three yards and then crawl back on the ice to dry land.

"He put his clothes back on and carried on. It was a foolish act of bravery."

Essex Fire Service confirmed it was not called to the incident.

Last week, Essex assistant divisional officer Stuart McMillan issued a warning about icy lakes and ponds.

"Even though this ice appears to be strong it can be eggshell thin and anyone who falls through into the water below could get trapped under the ice and would only be able to survive for minutes in the freezing water," he said.

"The most common cause is people chasing their dogs out on to the ice, and I urge people not to do this.

"It isn't worth the risk. Dogs will normally make it safely off the ice and back to the shore - the same cannot be said for people."