Lily, however, was intrigued by Snape and soon became good friends with him.
When she received a letter from Hogwarts confirming that she was a witch, Petunia wrote to Albus Dumbledore asking if she could also study there too.
She and Vernon chose not to attend James and Lily's wedding and the last piece of mail Lily sent her was an announcement of her son Harry's birth on 31 July, 1980, which she took one look at and promptly threw away.
Everything changed on the morning of 2 November, 1981, when Petunia opened her door to find a baby abandoned on her doorstep.
A letter had been left by Albus Dumbledore, explaining the circumstances of Harry's arrival, including the death of both her sister, Lily and her brother-in-law, James.
Vernon also took a fancy to Petunia and the two went on a number of dates, which mainly involved Vernon discussing himself and his narrow views of the world.
Petunia gladly accepted, but secretly worried what Vernon would think when he met Lily, who was then in her seventh year at Hogwarts.
As she was the only member of the family that had her sister's blood running through her, this ensured the protection of Harry and his family from Lord Voldemort and his Death Eaters.
She reluctantly agreed to take her orphaned nephew into her home and family, taking the responsibility to not tell Harry or anyone else about the fact that Harry was a wizard.
She eventually told Vernon about Lily being a witch on a date in his car that was parked overlooking a chip shop from which they had purchased battered sausage, and while he was shocked, he assured her he would not hold it against her.