Dom Joly: 'If Grandpa had died in the war, would I still exist?'

Up to London we go to see my dad march in the Remembrance Sunday parade. First we endure a stressful half an hour at home trying to persuade our kids to wear something vaguely smart. My son particularly resists this attempt to Little Lord Fauntleroy him. It takes me right back to being a kid myself – valiantly resisting efforts to make me wear a tie for the Easter church service. I've had a loathing of ties all my life and I'm pretty sure that this trait is genetic as my son is definitely heading that way.

The drive to London is smooth and easy. If only, in the words of Morrissey, every day was like Sunday. We drive right into town and get a parking spot at Hyde Park Gate, a stone's throw from the Cenotaph. We cross the Mall and buy one of the most expensive coffees known to man from a little booth in St James's Park. It's a posh part of town, so I wonder whether the extortionate price might be because they are using Kopi Luwak, the highly prized Indonesian coffee beans that pass through the digestive system of the palm civet before being harvested? Sadly, I can't be certain, although it certainly tastes like shit.

We take our usual places just opposite the rear exit to Downing Street. Moments after we arrive, the cannon goes off to mark the start of the two-minute silence. It's deafening and the kids jump out of their skins. Behind us a group of French tourists, unaware of the protocol, natter loudly to each other. They are roundly shushed and disappear shame-faced behind a tree.

There are always interesting people wandering in this area of Whitehall. We spot David Cameron. He spends a good 10 minutes glad-handing startled marchers. To be fair, he seems to be fairly popular among the veterans, and gets several large cheers from various groups. Ten minutes later, a little flurry of security accompanies Princes Edward and William as they walk from the Cenotaph, through Downing Street, to Horseguards. They are wearing Disneyesque red capes and huge, dangly swords. William just about manages to carry the look off, but Edward looks not unlike a pantomime dame.

In front of us a phalanx of electric wheelchairs advances gingerly. Its leader, a cheery double-amputee in a flashy electric carriage, does a couple of 360s and everybody claps. He beams with delight and does some more. Eventually we spot my dad marching with the Fleet Air Arm, their bowler hats bobbing up and down in unison. My kids are excited and we all clap and cheer wildly. My daughter, Parker, becomes contemplative: "Dad, lots of people died in the wars. That's why we are here, isn't it? If Grandpa had died, would I still exist?" She's a thinker, my little girl.

Our duty done, we all head off for the big lunch. Tradition dictates that we always go to Simpson's-in-the Strand. I'm not sure why. It's over-priced and rests smugly on its laurels, but the dining room is gorgeous and we always secure a huge, long table. My boy, Jackson, is surprisingly happy to be going to Simpson's. He jumps up and down excitedly all the way. I had no idea that a restaurant could have such an impact on him. Once inside, and seated, he appears deflated. I ask what's wrong. "Where's Homer?" He asks in a disgruntled manner. It appears that he has been expecting the other Simpsons.

But before long, a Yorkshire pudding almost bigger than him puts a smile back on his face. The meal takes four hours. Family events are curious creatures, but it's great to see my kids stare proudly at their grandfather. He might not be Grandpa Simpson, but they've got something even more special.