Tancock is the world record holder over 50m backstroke but with that event not an Olympic discipline the Exeter swimmer will be going for gold in the 100m this summer.
And while the 27-year-old certainly prefers the shorter sprint distance he has won international medals at the longer Olympic distance, most notably a gold in the 2008 short course World Championships in Manchester.
Tancock has already had a taste of Olympic action after making his debut for Team GB in Beijing four years ago, where he swam personal bests but came up short of a medal, finishing sixth in the 100m.
Mum Kim was in the crowd for those performances and despite the growing pressure surrounding Team GB athletes this summer, she insists her son will approach the event just like any other.
“Our trip to Beijing four years ago was a pretty incredible experience really all round,” said Kim, speaking at the P&G Thank You Mum campaign.
“Liam got through to 3 finals. He didn’t win any medals but to be honest it didn’t really matter. It was an experience that a lot of swimmers will never ever achieve.
“He swam the fastest he’s ever swam, you can’t ask no more than for somebody to do that – I felt very proud.
“I’ve also watched Liam gain a world record and that was probably the most amazing experience a parent could ever experience.
“It was emotional – a really emotional time. I cried. I just wanted to spend time with him but it wasn’t possible to spend time with him but he saw me in the audience and he gave me a wave and blew me a kiss and that was enough.
“The journey that we’ve had with Liam in the buildup to the Olympics has been quite amazing really. He’s achieved an awful lot I feel with no pressure from anybody. The key to all of it is that he’s enjoying it and having fun and that will be the same this summer at the Games.”
Kim admits that her son took like a duck to water from an extremely young age, something that resulted in mishaps on a number of occasions.
“Liam was very much taken to water to be honest from a baby,” she added.
“From quite a young age as soon as he could toddle along which was about 16 months really we were down at the beach and we had to keep a very close eye on him because he would end up fully clothed in the water!
“When Liam started competing he was only eight years old. We felt that it was really important to have some sort of balance between the swimming life that was starting to take off with Liam and the other interests and his friends and people around him and we just carried on with normal things that families would do.
“When he was 15 we received a phone call he got asked by the GB coach he was being asked to go to Australia.
“I was really, really scared and nervous about the fact he’d never left us before apart from going on a school trip or something like that. We went to the airport and said our goodbyes and…
“Obviously it was emotional, you see them walk away from you and you’re not going to see them for several months. But also I knew it’s what he wanted.
“My ethos for being a mum is for children to enjoy life. That’s the key as far as I’m concerned to any success.”
Watch Kim Tancock’s story at http://www.youtube.com/watch?v=5KH2Ya5BKCo&feature=youtu.be – the film is part of a series called Raising an Olympian from P&G, looking at what it is like to raise a world class athlete, through the eyes of their mums.
MORE: The latest football news
MORE: The latest tennis news
BIOGRAPHY: Nabil Fekir
BIOGRAPHY: Sokratis Papastathopoulos