Jaimie Milgate, 18, started experiencing only mild contractions on Sunday evening and thought she had plenty of time to get to Wodonga hospital.

But about 10pm, the pain intensified.

Miss Milgate’s mother, Sharon Quick, arrived to take her to hospital while the baby’s father, Josh Clifford, took the couple’s daughter, Taylah, to a relative’s house nearby.

But the family’s plans went awry as Miss Milgate’s water broke in the driveway of her Eltham Court home, forcing her onto her hands and knees in front of neighbours arriving home.

By the time the Mitsubishi Pajero reached McFarland Road, the baby was crowning.

Mrs Quick pulled over and called 000, receiving instructions on how to deliver her grandson.

But the aged-care nurse’s task was made even more difficult when she dropped her phone in the dark and had to proceed alone.

“I’ve got four kids but I’ve never been responsible for delivering one,” Mrs Quick said.

“I just really panicked, I didn’t know what to expect.

“But I was just happy that he was OK.”

Tyrone Riley Clifford, weighing 3.77kg, was born about 10.55pm, wrapped in his grandmother’s denim jacket until paramedics arrived to help Mr Clifford cut the umbilical cord.

The labourer, 20, had been on his way to the hospital after dropping Taylah off when he saw Mrs Quick’s car and stopped to find his son had been born.

Miss Milgate said the birth had been less intense than Taylah’s 13 months ago and she had laughed throughout the delivery at the absurdity of the situation.

“It wasn’t actually that painful — it was just good to get him out,” she said.

Mrs Quick yesterday began cleaning her car — starting by throwing out the front-seat cover.