She and her husband were 30,000ft in the air on a plane to Crete, she was 25 weeks into her pregnancy - and there were no doctors on board.
The jet had been diverted when her waters broke but Mrs Delemere knew that Alfie couldn't wait for landing.
Somewhere above Dusseldorf in Germany, as she sat in her seat with an air hostess and a passenger acting as midwives, he arrived, barely alive and weighing only 1lb 1oz.
Thankfully, flight supervisor Carol Miller was there. The woman described as "Alfie's angel" used a drinking straw to clear the boy's lungs, before carrying out mouth-to-mouth resuscitation and heart massage for half an hour.
Air hostess Carol Miller has been described as 'Alfie's angel' by his mother, after she took control of his delivery and immediate post-natal care
Last Mod: 24 Ağustos 2007, 10:10
She relied on her basic medical training, and a retired nurse and ambulance driver were also there to offer advice. The plane soon arrived at Gatwick Airport and Alfie was taken straight to hospital.
He was not out of danger yet, however. Doctors told Mrs Delemere, 31, and her husband Dominic, 28, that the boy, their first child, might have gone too long without oxygen.
Even when his condition began to improve after a few days, there were still fears that he could have brain damage. And after four weeks in hospital, he caught the bug E.coli.
But against all the odds, Alfie pulled through. He spent six weeks at St George's Hospital in Tooting, and was then transferred to the Newborn Intensive Care Unit at Scunthorpe General Hospital.
Yesterday, four months after the extraordinary mid-air drama, he was at home with his parents in Scunthorpe. Although still requiring oxygen and weighing only 5lb 5oz, his parents expect him to grow up to be a normal, healthy boy.
"I was really scared thinking he wasn't going to make it," said Mrs Delemere.
She had been checked by a doctor before taking the First Choice flight from Manchester to Heraklion on April 17, and had no inkling that Alfie would be premature.
"All the staff on board were shocked but they were brilliant," she said. Mrs Delemere also praised Miss Miller for her quick thinking.
Yesterday, the flight supervisor said: "I'm delighted to learn Alfie is at home. He was born very quickly and at first we weren't sure he was breathing so I just applied my medical training, cleared his lungs gently using a straw and then carried out mouth-to-mouth resuscitation.
"We were also lucky to have the support of a retired nurse and ambulance driver on board until paramedics arrived."
Captain Peter Thomas, who was flying the plane, said: "The whole crew showed exemplary professionalism and our passengers gave us their full support through an emotional time."
Mr Delemere, a steel worker, said he and his wife were delighted Alfie was recovering well.
"I would like to thank everyone involved for supporting us in the air and on the ground. We can't begin to thank Carol enough for saving Alfie's life. We are really happy he is home."
The couple have no immediate plans to return to Crete but the airline has promised all three of them a free trip to Cuba once Alfie can fly.
Like most airlines, First Choice Airways allows expectant mothers to fly up to 28 weeks into the pregnancy. At 28-34 weeks the company requires prior notification, a medical certificate of fitness to fly and the stage of pregnancy for the homeward journey.