Dad of four, Harry Wallop, braces himself for a trip to Granny's for lunch.

Saturday lunch and we're off to Granny and Grandpa's. As we sit in traffic, the topic of conversation - with the inevitability of Jamie Oliver publishing a cookbook every Christmas - turns to food.

"What are we having for lunch?" asks my daughter, whose entire memory bank consists of meals she's had. Long-forgotten trips to museums are remembered thanks to the chocolate cake in the cafe; she can remember the quality of the biscuits doled out during a walk up a Lake District fell. Not the view, nor the majesty of nature in all its glory - but whether we remembered to pack the bourbons.

"I think it's sausage surprise," I answer
"Ooh, I love sausage surprise," the daughter answers.
"What's sausage surprise?" asks the youngest one, with a hint of fear in his voice.

Lunch at Granny and Grandpa's has become a battle ground in recent years.

Sausage surprise is when Granny palms off a selection of random sausages that she has amassed in the freezer after buying packs of six, but she and Grandpa have only eaten four. Pairs of Lincolnshire nestle in the freezer next to some pork and apple ones, alongside a couple of Cumberlands. It's sausage roulette, a pork-based rollercoaster. What will you get?

"Will there be vegetables?" asks the youngest, unconvinced by the appeal of sausage surprise and the family's fussiest eater.
"Well," I say, trying to put on my most comforting voice, "Granny has told me she is cooking carrots especially for you, because she knows you like carrots." He smiles from the back seat. "But, I think she might also be cooking broccoli. And if she gives you broccoli, it's very important you just have a couple of mothfuls, okay?"
"Ding it!" he says, slapping his forehead.

Lunch at Granny and Grandpa's has become a battle ground in recent years as the unstoppable force of four young children meet the immobile object of Granny's punctiliousness.

Some of it derives from her age and the fact she has enjoyed living with Grandpa for the last 20 years without any children in the house. Her home is like a small, badly-curated museum - without the protective glass cases. Every conceivable surface is covered in tiny knick-knacks: ceramic apples, miniature Chinese cups and saucers, delicate sculptures made of very snappable wood. To an adult they are mildly diverting curios, or clutter - depending on your view. My children, however, see the objects like Catherine Zeta-Jones saw the red beams in Entrapment, namely, somthing to avoid, but only by slithering their entire bodies as close as possible to them. Sean Connery, in the film was left in awe at Zeta-Jones' athleticism, but my mother is always aghast at the close shaves and near misses as the children run around. Her being on edge turns me from Relaxed Dad into Victorian Father. "Will you please be careful!" I shout at them, in an attempt to pre-empt my mother having a seizure.

She thinks my children have ropey table manners but believes she's doing her grandmotherly duty by highlighting this.

At the table, however, is where the real tensions rise. She thinks my children have ropey table manners, especially the youngest (and she's correct in this assumption) but believes she's doing her grandmotherly duty by highlighting this.
"What's for pudding?" asks the youngest after he's finished his sausage surprise.
"What's the magic word?" his grandmother says.
The youngest looks baffled. His sister elbows him, while his eldest brother says slightly piously: "You need to say 'please'."

The youngest laughs. He thinks this is all terribly amusing - until my mother repeats her request, this time more sternly:
"Come on, what's the magic word?"
"Please," he answers resentfully.

If good manners are all about greasing the wheels of social interaction, we've put a spanner in the works.

I then feel compelled to lecture the youngest on the importance of asking nicely just so that I can avoid the silent but stony judgement that I am A Bad Parent, which is - of course - the subtext.

The atmosphere plummets to almost the temperature of the ice cream that is then served. If good manners are all about greasing the wheels of social interaction, we've put a spanner in the works.

What makes this whole episode so trying is that it is a carbon copy of what happened on a regular basis with my second child, who is now 14 and has impeccable, charming manners. But he was a monster when he was a toddler, saving his worst behaviour for weekend trips to his grandparents, knowing instinctively this would have the greatest effect.

Children grow up. They learn - usually with a bit of gentle encouragement rather than a hectoring admonishment. It's possible that Granny thinks his model behaviour is as a direct result of her forceful interventions a decade ago. Maybe.

I just wish the sausage surprise could be enjoyed without the tutorials.