Soldiers have been drafted in to evacuate homes around a storm-battered bridge after it started to collapse, prompting fears of flooding and a gas explosion.
A severe flood warning has been issued for the bridge over the River Wharfe in Tadcaster, North Yorkshire, with the Environment Agency warning locals to leave immediately because of a "significant risk to life".
The 18th century bridge started to collapse into the swollen river around 5pm, with a crowd gathering as masonry fell into the swirling torrent.
People watching ran as a wave headed towards the bank and a strong smell of gas came from pipes left visible in the gaping hole.
Emergency services arrived quickly before soldiers were deployed to evacuate people from homes and set up a 200m cordon, saying it was "due to fears of a gas explosion".
An Environment Agency spokesman said: "This severe flood warning has been issued due to the structural failure of Tadcaster Bridge over the River Wharfe in Tadcaster.
"Significant flooding is expected in the Tadcaster area. Those in this area are advised to evacuate immediately.
"The situation is serious and there is a significant risk to life. Please follow the advice of the emergency services and officials in the area."
North Yorkshire Police said homes either side of the bridge were being evacuated, with residents being taken to a rest centre at Tadcaster grammar school.
It came as flood-ravaged areas of northern England braced themselves for further damage as Storm Frank batters the British Isles with torrential rain and gale-force winds.
Areas of Cumbria and Yorkshire which took a hammering from Storm Eve are on high alert as the latest weather front sweeps in overnight.
Tadcaster is 10 miles from York and has been affected by flooding caused by storms in recent days. The bridge had already been closed due to fears over its structural safety.
Nigel Adams, the Conservative MP for Selby and Ainsty, said he had been on the bridge with Communities Secretary Greg Clark earlier on Tuesday.
Visiting the scene he said: "It was a few hours before it collapsed. We did go on to have a look at some of the damage. In hindsight, we shouldn't have been on it. But I thought it was important that I showed the secretary of state the severity of the damage and the impact.
"We are where we are now. We need to try and ensure that it's repaired as soon as practically possible and that every possible resource be available to the highways, to the county council to make that happens."
The Environment Agency (EA) earlier warned of the potential for further significant flooding, especially in Cumbria, while floods minister Rory Stewart said a potentially "very bad situation" lay ahead.
In many areas the ground is still saturated from previous downpours and river levels remain at record highs.
Flood waters are receding but across the north of England more than 6,700 homes have flooded in the past week.
Elland Bridge, between Huddersfield and Halifax in West Yorkshire, has also been closed after the carriageway crumbled and collapsed after the floods.
Police also urged people in Kendal, Cumbria, to get out early and while it is still calm to do their shopping before bad weather hits again.
As anxious residents and businesses brace themselves for a fresh onslaught Sir Philip Dilley, the head of the EA, is returning to Britain from a family holiday in Barbados.
Sir Philip, who has faced criticism for his absence, is expected back in the next 24 hours. It is believed that a visit to the flood-hit region will be an early priority.
Craig Woolhouse, the EA's director of incident management, said: "The weather continues to be hugely challenging, with more rain threatening to cause further flooding in Cumbria and Yorkshire on Wednesday and through to Friday.
"We urge communities and visitors, particularly in Cumbria to prepare and not to walk or drive through flood water."
There are currently four severe flood warnings, 47 flood warnings and 84 flood alerts in place across England and Wales.
Scotland is also bracing itself with Met Office amber "be prepared" warnings issued for Wednesday in all mainland regions outside the Highlands.
A red weather warning has been issued for the Isle of Man overnight, with up to 100mm (four inches) of rain expected on high ground.
Large parts of Ireland are also braced for another winter battering weeks after Storm Desmond caused serious flooding in many areas of the island.
York's Foss barrier is now up and running, the EA said, after soldiers were drafted in to help with repairs. Emergency work was carried out on the defence system after high river levels flooded the pump room and hit the power system.
An army Chinook helicopter was used to drop portable power generators onto the barrier's roof on Monday and severe flood warnings that had been in place for York since Boxing Day were lifted on Tuesday after four of eight pumps started working again.
The EA's's decision to open the barrier sent flood water coursing through the city streets and left many property owners wondering whether their buildings were put at risk to save others.
The EA said it took this "difficult decision" in "a rapidly moving situation" to reduce flood risk to the residents of York.
The Coastguard on Tuesday warned people to fight the temptation to visit coastal areas to take storm selfies.
Weather warnings for ships are currently in place for coastal areas from Aberdeen to Shetland and from Stornoway in the Outer Hebrides down through Belfast, Holyhead on Anglesey, Milford Haven and Falmouth in Cornwall.
Commander Mark Rodaway said: "We've all seen the dramatic pictures of flooding inland and seen from previous years, some equally dramatic images from coastal storms.
"Do not be tempted to go out and take those photographs yourself. No photograph or selfie is worth risking your life for."