The dog, called Jeanie, became trapped in the freezing pond at Oak Road playing fields, 20 metres from the embankment, at lunchtime on New Year's Eve.

The 28-year-old passer-by, who has not been named, went to help the woman who owned the dog by first wading and then swimming out into the icy water to save it.

Sub officer Tony Conroy from Humberside fire and rescue service said it was a brave act, but no-one should attempt a rescue on ice, without the help of the emergency services.

"Luckily for him, it didn't end in tragedy," he said.

"You never know what's underneath the ice, the depth, whether it's on a tide, or the dangers that can unfold, bearing in mind that hypothermia can set in within seconds.

"We strongly advise that nobody enters a frozen waterway."