Forget chestnuts roasting on an open fire and Bing Crosby - white Christmases are about to be consigned to history.

Experts said today it was unlikely snow would fall on December 25 within the lifetime of today's adults.

Snow is becoming an ever-rarer phenomenon in Sussex and could disappear altogether if climatologists' predictions about global warming turn out to be correct. Sussex has had nine white Christmases in the last century and only one in the past 45 years - in 1970.

Lewes Liberal Democrat MP Norman Baker, who is investigating the impact of global warning, was given the statistics after asking a series of written questions in Parliament about the amount of snowfall and projected snowfall in Britain.

To be an official white Christmas, a flake of snow must be observed to fall at specific sites between midnight on December 24 and midnight on December 25.

It counts even if it falls mixed with rain and there is no covering of snow on the ground.

Since 1957, there have been 25 instances of white Christmases around Britain yet, because of global warming, the future chances of snow on Christmas Day will drop by a third by 2010 and by more than two-thirds by 2050. Mr Baker said: "Britons will soon be left with only dreams of a white Christmas, as the chances of it actually happening become more remote.

"Global warming is the main reason for this shift in seasonal weather and is responsible for changing the world as we know it. It is not only Christmas that will be affected. In the New Year we can expect to see more of the extreme weather, floods and gales suffered across the continent this year.

"This is a global issue, but the UK Government needs to make reducing greenhouse gases one of its top New Year's resolutions."

Argus weatherman Ken Woodhams, who has been monitoring the weather in Brighton for 50 years, said: "There is something in what Mr Baker says. The incidences of white Christmases in Sussex are on the decline.

"There must be a scientific reason for it. We have not had a white Christmas in Sussex since 1970 when snow fell on December 24, 25 and 26, and in 1962, there was no snow on Christmas Day in Brighton, but a heavy snow fall on Boxing Day."