Rosalinda Hardiman was in sight of Calais when she began to slip in and out of consciousness.
Her support crew had to haul her out of the water, bringing an end to the amazing challenge of swimming the 21 miles using just her arms.
But the determined 56-year-old, who was left in a wheelchair after being struck down by polio at the age of six, has vowed to attempt the swim next year.
'I was so nearly there,' she said.
'At the time I did not know it was that short a distance. But they left me in the water as long as they could, and they made the right decision – I could not have gone on. I still feel 25 hours is a huge achievement and it was a great experience.'

Rosalinda is the second local woman to experience the heartache of having to abandon a Channel crossing on the last lap - read about Anna Ardley's attempt.

Rosalinda, of Byron Road, in Copnor, Portsmouth, had been waiting all summer for a chance to attempt the swim.
Last Tuesday she received a call saying a break in the weather meant she could finally get under way.
She drove to Dover and at about 5pm last Wednesday entered the freezing waters.
But after 18 hours of swimming an old shoulder injury from a car accident started to cause her agonising pain.
She said: 'It got to the stage where it was so painful I could barely take my arm above the water. By the end it was just awful.
'I remember somebody was in the water with me, but I don't remember them pulling me on board – I have no idea how I got on the boat.'
After 25 hours and 14 minutes of swimming Rosalinda was just 0.7 miles from the finish line.
She said: 'I was vaguely aware what had happened, but they did not tell me how close I was until I got back to Dover.
'When I was on the boat I just felt relieved that I was out of the sea because I had been in so much pain.
'I was lying on the deck and really started to feel cold. I had difficulty breathing, I was wheezing – I think because of the cold.
'I do think what if I could have made it just that little bit extra, but I could not have gone on.
'I could see the French coast. I could see little houses on the shore, but they were not getting any closer.
'In two hours they did not get any closer.'
Back in Portsmouth, still suffering from aching muscles, she said: 'I estimated it would take me 20 hours and if I had been quicker I may have completed it. I will try again next year – and I will just have to speed up.'