John Smith's Grand National, Aintree, Saturday, 1615 BST
BBC One/BBC HD/BBC Radio 5 live/online, with other races also across the BBC 8-10 April. National highlights: Sunday, 0030 BST, BBC Two
Twiston-Davies will be back at school once the Easter holidays are over
Amateur jockey and A-level student Sam Twiston-Davies, 17, will on Saturday aim to be the youngest winner of the Grand National since Bruce Hobbs booted home Battleship in 1938.
He rides outsider Hello Bud for trainer, and father, Nigel 22 days after the most significant of his 15 winners to date, Baby Run in the Foxhunters' Chase at the Cheltenham Festival. That day Nigel Twiston-Davies had three winners in all, including Imperial Commander in the Gold Cup.
He is also the only current trainer to have won the National twice, with Earth Summit (1998) and Bindaree (2002).
Sam, who lives with his parents at their base in the Gloucestershire Cotswolds, had his most recent success on Love for Tara on Tuesday, up at Wetherby, west Yorkshire. Here, he tells BBC Sport how he has been preparing for the biggest ride of his life.
"It was a brilliant party after we had those three winners at Cheltenham, but I drove my mum to one of her parties and one of my best mates had a ride the next day so I didn't stay up too late. I don't drink anyway, I prefer Diet Coke.
"I don't mind driving to and from racecourses, however far away they are. I just make sure I've got plenty of music to listen to.
"It was a long drive home after my ride on Tuesday [170 miles] but I had won the race so that made it much easier.
"Every winner you get helps your confidence, but you can be brought back down to earth pretty quickly by a fall, or if you get beaten on a favourite.
"I've had one ride at Aintree at a night meeting in the summer. It was a hunter chase, and it wasn't round the fences they use for the Grand National.
"I've been preparing for Saturday by schooling Hello Bud at home. The majority of horses just take to the Aintree fences normally.
He'll eat the four and a half miles for breakfast and hopefully he'll eat the fences for breakfast as well
"I'm going to speak to Carl Llewellyn [Twiston-Davies' assistant, and two-time winner of the National] and walk the course with him tomorrow.
"I'm also going to chat to Denis O'Regan [jockey of Black Apalachi on Saturday] as well, and sit down with AP McCoy. I'll need as much help as possible and need to get every little fact I can into my brain.
"Hello Bud is a legend to run. You couldn't get a horse more keen than him before the start but when he starts his race he's not too keen and he gallops and jumps like an absolute bunny.
"If you see a stride before a fence he lets you take it, if you don't see one then he usually does. I hope he runs well, he's an unbelievable horse.
"He is purely a stayer. He'll eat the four and a half miles for breakfast and hopefully he'll eat the fences for breakfast as well.
"I want to be handy, to stay up there and track the leaders but he might not have the speed to get to the front group to begin with.
"Hello Bud goes on every ground, but runs his best on good to firm ground so if the sun tries to come out over the next couple of days that will help us. But if the ground does stay on the soft side of good they might go that little bit steadier early on which might help him.
Bindaree (2002) - the second of two Twiston-Davies Grand National winners
"I'm very excited for Thursday because I'll be riding Baby Run in the Foxhunters' Chase, but on Saturday I'll be very nervous.
"It'll be a test to be riding in the Grand National but I'm also very honoured because it's a dream to ride the National fences. I'll need to make sure I get lots of sleep on Friday night.
"Obviously I will be concentrating on what Hello Bud's doing but I ride Ballyfitz at home regularly so will want to keep a little eye out for him.
"I'm doing A-Levels at the Cotswold School at Bourton-on-the-Water - Business Studies, PE and ICT. I'm in my first year so don't finish until summer 2011.
"But the A-Levels are just something to fall back on if I break my neck or something as a jockey. I'll be turning pro as soon as I've finished my exams.
"Actually I was quite keen to get straight into riding after my GCSEs but my mum and dad were quite keen I did A-levels first.
"If it all goes well, I'll aim to start out as a freelance jockey. I went to David Pipe's yard in the summer and loved it there. I love riding, I'd be happy to just ride out every day."