Brendan Pickering dialled 999 when he saw the structure crumbling and himself turned away a car and two lorries in the dark before police including the tragic cop arrived.
"I saw the poor policeman who died come up on the other side with his lights flashing," said Brendan, 47, who used to play for local team Workington.
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"I saw the bridge was moving, pitching and bucking because of the pressure from the river. A section went and it must have set up a domino effect because the whole structure went. It was an awful tragedy."
Last night more eye-witnesses began to give their dramatic stories of the Northside Bridge collapse which swept PC Barker out to the Irish sea. The body of the dad-of-four - who would have celebrated his 45th birthday yesterday - was found on a beach 15 miles away.
Grieving townsfolk left flowers close to the scene. One said: "The bridge just looks like it has been bombed - there is nothing left." The wreckage was sealed off yesterday. Twisted pieces of steel are all that remain. Rubble from the structure lay in mounds on the river bed as the fast-flowing water crashed over it.
More than a dozen other potentially dangerous bridges in the county were closed.
And as the floods slowly began to subside, the full-scale of the terrifying damage in the towns of Cockermouth and Workington - in which two months of rain fell in a single day - was revealed. More than 1,400 houses have been abandoned across the county. Survivors spoke of a "Dunkirk spirit" among the hardy Cumbrian people as victims whose homes were swamped found shelter with relatives and even strangers.
But the death of PC Barker remains the symbol of the aftermath of England's wettest day on record.
Mr Pickering told how he had been walking his dogs past the bridge over the River Derwent at 4.40am on Friday when he heard strange noises.
He said: "I heard this whooshing noise so I went up on to the bridge. It seemed part of it was missing.

"There was a car coming on so I stopped him. I phoned 999. I heard the first section break as a policewoman and a male colleague arrived. She shouted at us to get off."
Later she told him PC Barker on the other side had gone into the water. "She was obviously very upset but she never left that bridge. That took some guts."
David Hoare, a Stagecoach bus route inspector, told how he saw the bridge collapse minutes after arriving at the scene with colleague Kevin Sheehan. The 63-year-old said: "We stopped right in the middle of the bridge. There was a car parked there. The driver said , 'The bridge has gone'. You could see a crescent-shaped crack up the wall and along the road. The bridge wall and pavement had gone.
"Some of the road was missing too. I ran towards a bus coming towards the bridge to stop it. There was a lorry and tanker too.
"Then I guided Kevin in the van off the bridge. Suddenly it collapsed. I was only 10 yards away when it went. I feel very, very fortunate."
In Workington many of those driven from their homes stayed in hotels as the flood waters rose.
Jonas Enberg, 35, said: "We just took the decision ourselves to get out and we did it just in time. The torrents were very strong and I was just hoping I didn't get swept away. We have lost everything."
In hard-hit Cockermouth Jean Gibson, 78, took in her son and his family after their home was destroyed by five foot high waters.

"I lived through the Second World War - like then everyone is doing all they can to help each other," she said.
Chris Frain, 37, who lives by the River Cocker with wife Rachel, 35, said: "The water just came gushing through the house, the furniture has been tipped all over the place. Everyone has been helping out."
George Jackson, 60, had to be rescued by an RAF helicopter. When the river burst its banks in the early hours, water gushed up through his toilet and sinks, then seeped up through the carpets.
"I was shouting 'Help! Help! Help!' A chap came up from the mountain rescue and put me on a dinghy," said George. "We went to the vets clinic nearby, and they winched us up in a helicopter."
Stunned Cockermouth residents were shocked by the stench from the sludge covering the pavements, gardens and walls. Furniture was piled into the streets as people tried to clear their homes.

Disabled Anne Burn, 77, had to leave all her possessions behind when she was evacuated. She said: "I'm left with nowt - I didn't have time to get anything out. But I've been overwhelmed with kindness."
Phil Rothwell, from the Environment Agency, said more than 1,400 properties across the county were flooded. Cockermouth was the worst affected with 600 homes wrecked by the rising waters.
He said water levels were expected to fall over the weekend despite further rainfall.
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This article has 10 comments
Rest in peace bill. One in a million!
By Cumbrian PC.. Posted November 23 2009 at 9:04 PM.
My heart goes out to the families in Cumbria and to the family of PC Bill Barker.
I live in Ireland but have a lot of friends in Cumbia and have spent some happy times there. I have spoken to most of my friends and what they are telling me is heart breaking, I wept as I watched it on Sky News. God Bless You All in your troubled times.
By Maureen Farazian.. Posted November 23 2009 at 3:25 PM.
i didnt realise workington was affected so bad . i was only there a couple of weeks ago . my sympathy goes out to all that was affected and especially to the family and friends of pc bill barker . R.I.P.
By james brown.. Posted November 23 2009 at 2:59 AM.
Truly horrifying.All those poor people who have lost their homes.My thoughts are also with PC Bill Barkers family,he was a true hero ,a very brave man.
By Jane McEvoy.. Posted November 22 2009 at 11:12 PM.
So where exactly was the billion pounds spent that has been allocated as part of flood management on a yearly basis? Obviously not on reinforcing the bridges and cleaning the drains!
By Maggy.. Posted November 22 2009 at 8:56 PM.
My heart and thoughts go out to those poor people of Cockermouth, who have lost their homes and memories of a lifetime. And to the dear family of the heroic policeman Bill Barker, who lost his precious life to save others. RIP
By Dorothy Lake.. Posted November 22 2009 at 6:04 PM.
A true hero. My condolences go out to his family, friends and colleagues. R.I.P Sir.
By Deborah Mitchell.. Posted November 22 2009 at 1:49 PM.
for someone to give their life to save others is the ultimate gift.God bless him and his dear family. ,
By vanessa.. Posted November 22 2009 at 10:21 AM.
R.I.P.
By jason.. Posted November 22 2009 at 7:56 AM.
Horrifying. I really feel for all that are suffering. To lose your home and so on is devastating. The loss of life though is a million times worse. Possessions can be replaced in time. A life can't.
By Gillian.. Posted November 22 2009 at 6:59 AM.