Britain's big chill led to the spectacular sight of the sea freezing along part of the Dorset coast as well as in parts of Bristol's historic Harbourside.

Sub-zero temperatures overnight on Tuesday saw frozen sea at Poole Harbour in Sandbanks, Dorset, and Bristol Docks yesterday morning.

A half-mile stretch along the Dorset shoreline reaching about 20 metres out to sea was covered in ice on the exclusive peninsular, home to Tottenham Hotspur manager Harry Redknapp.

Southern England, normally immune to the worst of the weather, was gripped by conditions chillier than parts of Iceland and Greenland overnight as temperatures fell close to -12°C.

The temperature fell to -8°C in the Bristol area causing parts of Chew Valley Lake to freeze over. It took the swans by surprise and two of the birds had to be rescued after they got stuck in the ice.

In parts of Wiltshire, temperatures as low as -16°C were reported.

The big freeze also left hundreds of homes in Bristol without water or with burst pipes. Callers jammed Bristol Water's switchboards as the rang in to report problems.

Bristol Water said staff have been working round the clock to fix leaks and burst water mains with the ones affecting homes being repaired first. Fifteen leaks and bursts were repaired on Tuesday night alone at locations across Bristol and North Somerset.

Bristol Water spokesman Jeremy Williams said: "Every effort is made to restore supplies to normal as quickly as possible but we do ask customers to bear with us while we tackle the problems in extreme weather."

Hanham Abbotts Junior School, near Bristol, was closed yesterday after its central heating system failed. A special educational unit for 21 pupils at Shirehampton, Bristol, and part of a referral unit for children at Weston-super-Mare have also closed because of boiler failures.

In Gloucestershire, parents were told to collect their children from Minsterworth C of E Primary School in the Forest of Dean yesterday afternoon after a heating failure.

Engineers were called and the school said it hoped to re-open today.

Motorists were also badly hit by the continuing Arctic conditions.

There were claims that the Highways Agency had "over-gritted" a slip road at the top of the M32 motorway in South Gloucestershire and it had to be closed because so many drivers were losing control.

But the agency said motorists were driving much too fast for the conditions which was the real cause of the problem and they should slow to 20mph on slip roads.

Milder weather was predicted last night but forecasters warned driving conditions would be more perilous this morning with freezing fog and black ice predicted on the roads.

Fears were also growing for the welfare of vulnerable people amid speculation gas prices were set to soar.

Police said icy roads also caused "treacherous" driving conditions across Dorset with traffic incidents reported on Wednesday morning.

About 20 pupils were temporarily stranded when a single-decker bus they were travelling on collided with a Ford Fiesta on Rowlands Hill in Wimbourne.

No-one was hurt and a minibus took them to Queen Elizabeth's School in Wimborne.

In Bristol, some water ferry services were suspended yesterday after parts of the route were frozen over.

Thanks to the cold snap, heating bill payouts to pensioners and the vulnerable have now topped £100 million as the Government stepped in to help.

The £25-a-week payout is triggered when an area's average temperature falls to freezing or below for seven consecutive days. However, the National Pensioners' Convention warned 12 elderly people could die every hour due to the cold and 260,000 pensioners had died from hypothermia since 1997.

Nikki Berry, a forecaster for MeteoGroup UK, said today would be less cold but the weather would last until the weekend. The current freezing conditions have been caused by Arctic air sweeping across Scandinavia and over the North Sea.

It has caused birds to flock to domestic gardens as frozen conditions make it "almost impossible" to find natural food sources, wildlife charities said.

The cold weather is bringing all sorts of unusual birds to homes, the Royal Society for the Protection of Birds revealed.

Increasing numbers of waxwings, reed buntings, yellowhammers, redpolls, grey wagtails, redwings and fieldfares are being spotted on feeding tables across the country.

Val Osborne, of the RSPB, said: "We always get lots of calls from people reporting an abundance of birds in their gardens as they come in search of food at this time of year.

"But this year there has been a noticeable change in the species people are seeing in gardens.

"We would expect lots of garden favourites like robins and blackbirds and there are still plenty of those around but to see things like grey wagtails and bullfinches is more unusual."

Elsewhere, 35 Bewick's Swans – who travelled 1,864 miles from Arctic Russia to spend winter in the relative warmth of the UK – were yesterday contending with a frozen lake at Slimbridge Wildlife and Wetlands Trust, , Gloucestershire.

The free Home Heat Helpline on 0800 33 66 99 offers support for people suffering from fuel poverty, or those concerned about friends or relatives. People vulnerable to the cold can call the number to access free grants for insulation and reduced energy tariffs.