A baby's birth is surely the most joyous of all family events. With a new life and fresh innocence, the bonding of two families cooing over the new arrival seems inevitable. My partner is expecting our first child and her liberal Indian family have gone into overdrive to help us prepare for the baby and move to a new home. They are carrying boxes, buying appliances, giving us things for the baby and delivering unbelievable homemade Indian food.

We're grateful, not just for the amazing dishes, but for the support they have given us during the stress of house-buying and pregnancy.

In contrast, I'm getting the opposite of support from my father.

I've always know my dad was racist. I've disagreed with him all my life, not that he's noticed. No one else in the family shares his views, but he is oblivious to the opinions of others.

When it became clear that Mira and I were committed to being together, I tried to ease my father into the news, first telling him of my Indian friend, who was born in Kenya. He wasted no time in registering his objection. "Don't introduce her to me. I'm trying to send them all back," he harrumphed, about the sweetest girl I'd ever known.

Meanwhile, I was meeting, and being welcomed by, Mira's family. We went to her cousin's wedding in Gloucestershire and I was struck by the fondness between the elder uncles and aunts and the young nieces and nephews. Everyone mucked in to help, all the generations danced and celebrated together. It hit me that this is what a family is supposed to be like. They had a lot of love for each other and weren't shy about showing it. They also knew how to enjoy themselves. The laughter and dancing went on all night, and one or two of the old boys could be seen loitering by the door in the hope that the young ones were smoking more than tobacco. The ladies howled as a saucy aunt took the opportunity to cop a feel of my backside as I shook my generous booty.

On returning to London I visited my parents. After spending three happy days with Mira's family, it only took an hour with my dad for me to despair. I was subjected to a relentless torrent of bitterness about the government, immigration, television, the NHS, Tuesdays … it was all terribly, irredeemably foul. And it was all better in his day when you could leave your door open and be a hateful racist without anyone batting an eyelid.

Out of earshot of Mum, my dad told me I should "be careful" with Mira. It was a bit late for that, as we had just found out we were to have a baby, though it was too soon to make an announcement. His warning wasn't based on any knowledge of the person she is but on his assumptions about race and immigration. He suggested I would soon be putting up her relatives, and, even more absurdly, harbouring terrorists.

Depressed by his descent into risible paranoia, I took my leave, wondering how he had become such an ogre.

"He wasn't always like this," Mum said at the door. "I don't know what happened to him."

My dad was born into a large, poor, south London family in the 1920s. Seventeen at the outbreak of the second world war, he became a stoker in the Royal Navy. By the time he was 21, he had sailed round the world, been sunk twice, seen good friends die and earned the eternal thanks of his country. By the time I was 21, the greatest suffering I had experienced was bleaching my hair.

When he introduced my mother to his parents, my grandfather walked out. My mother's from Tipperary and the Irish were "coming over here, taking our jobs" and all that jazz. A generation on, not much has been learned.

Dad worked hard all his life and retired in his 50s. He had no idea what to do with himself without work to define him and, still haunted by his experiences in the war, he became an alcoholic. It took the threat of divorce from his devout Roman Catholic wife to drag him back from the brink.

Since then, his world has narrowed. He mourns a lost England, unable to recognise the multicultural country it has become as the one he fought for. "That's not patriotism," I tell him. "It's nostalgia."

In the last couple of years, he's spent all his time in a wheelchair and has only left the house to vote – for the BNP. The Daily Mail, television and the occasional like-minded visitor inform his perspective. So he has become a sour, entrenched, dogmatic bigot who only hears views that chime with his own racist – and even fascist – position.

With Mira pregnant, I knew I had to introduce her to my parents before announcing our news, lest I expose her to an even more difficult scenario. ("Hi Hitler. Let me introduce you to the mother of your Indian grandchild.")The reaction of friends and siblings to our happy surprise has been joyous and life affirming. I was a little nervous about telling my 23-year-old daughter, Dixie, that she was going to have a brother or sister but she was pragmatic and honest. She didn't know how she would feel about sharing her father for the first time, but she wanted to be involved. She is the reason I know how uplifting raising a child is. She constantly fills me with pride, not because she's doing so well, but because she's a great addition to the world.

Her first reaction was, "Ha! Your life is over." Her second was, "What did Granddad say?"

Mum assured me Dad would behave when I brought Mira over to meet them. He would only have to be civil for five minutes before the three of us went out. "You're different to what I expected," he said, shaking her hand. "I heard you were from Kenya, so I thought you'd be a 6ft Zulu with a bone through your nose."

Really. That's what he said. And that's him on his best behaviour. If only Prince Philip had been there to laugh. He asked a few questions about her family background – very important to any self-respecting doctrinaire – and we parted. The introduction had gone well. Mum thought Mira was lovely and Dad hadn't expressed an opinion. I couldn't ask for more.

Mira had said it would be harder for me than for her, and she was right. She was untroubled before the visit and untroubled afterwards. She hasn't experienced much racism since coming to London at the age of nine and has a soft spot for old duffers. She's not easily offended and was quite happy to meet my dad and engage him, should he kick off. It might have been better than the faux civility.

Having breached introductions, it was time to drop the bombshell. I enlisted my brother and sister to join me, mostly so my dad could see how normal people react to good news.

Loyalty, respect and decency are central to his generation's values: loyalty to the country and your family. So could I expect him to be loyal, respectful and decent when I arrived to tell him that, after 23 years, I was to be a father again?

There's really only one way to put it. "Mira and I are going to have a baby!" Cue almost universal joy, screams and congratulations. Mum was thrilled and my brother and sister were delighted. "That's wonderful!" Mum said.

"Is it?" huffed my dad, who wheeled himself out of the room to calm down. The only person not to have congratulated me on the news was my father. He stewed all day, silently.

Meanwhile, Mira's family were cranking up to hysterical levels. Offers of help abounded and stamp-duty money was proffered for our new home. Food deliveries were increased, and I was getting progressively larger portions.

I was even more endeared to them by a tale from Mira's childhood. During the summer holidays, the extended family would cram into a car, including aunts, uncles and cousins. The kids would be in the boot and the adults squeezed into the seats as they headed excitedly for the airport. There they would sit in the departure lounge and watch the unfolding drama of people parting, while they had a picnic. For a treat they would go to arrivals.

I had to wait some weeks before my dad could broach the subject. He was "disgusted", he told me, that I was having a child "out of wedlock".

I laughed. "How could I marry an Indian girl with you?"

"I wouldn't come!" he barked, thinking it quite rational that I should marry because of his sudden bout of religious propriety, even if he wouldn't attend. But I knew it was his way of protesting without mentioning his real objection – her ethnicity was the problem.

There have been many mixed marriages in Mira's family, so race is not an issue for them. They, too, would like us to be married but accept that it is our choice.

Dad said he couldn't believe how "daft" I'd been, not even considering that I might be happy. He wanted nothing to do with it. He didn't want to know anything about the baby's progress. He maintained it was my Roman Catholic mother's feelings that concerned him, as according to him, she was secretly disgusted too.

That he hadn't even spoken to my clearly delighted mother about their imminent fifth grandchild seemed inhuman to me. I resented his lying about her to express his own opinions. I returned a similar level of vitriol, making clear that it was he, not me, who should be ashamed of his behaviour. We left it there. I told him not to bother getting in touch if he wasn't going to apologise and, predictably, I haven't heard from him.

For the first time in my 49 years we're not talking. We've never had much in common, but talked most weeks, making each other laugh about football and family. I wasn't surprised, or that hurt, by his diatribe, but I was disappointed to see his lack of interest in my happiness and disrespect for my choices. He didn't ask about the woman who will be the mother of his grandchild, or how happy we are. His concern was how he felt about my situation: a triumph of ideology over parental concern.

Some have questioned the wisdom of a dispute with a father who is 88, in case "something happens". I can understand that, but it doesn't allow me to forgive the unforgivable. Having provided for it, he has dominated the family, laying down the law, mostly unchallenged. I'm not going to allow him to disrespect the woman I love, her family and our unborn child, and then go on to chat about the woes of Charlton Athletic.

It's a shame he won't know Mira. He would love her to bits if he could see past the colour of her skin. To me, it's shameful he has attempted to poison such a proud and blessed moment in his son's life. I can only hope the sight of a new baby will soften his silly head, but I'm not confident.

It took another generation to put it into perspective. As my daughter Dixie said: "Think of it this way, Dad – he'll be the last racist in the family."

Names have been changed