Lions back row ace Uttley confesses for the first time that his crucial try during the tour's final match should not have been allowed.
Match referee Max Baise also acknowledges this, describing his decision to award the try as "the worst decision of my life".
The admissions are made during two special documentaries, "The Invincibles", commissioned by Sky Sports from BAFTA-winning André Singer. They include never-seen before home videos - a 1970s 'Living with Lions' - shot by the players, original match footage, and interviews with many of the touring party.
Other confessions during the series include:
- Fergus Slattery's discussion of breaking Apartheid laws and sneaking into Soweto and District 6 to see how life really was at that time.
- South African Minister for Sport, Makhenkesi Stofile, admitting how young black people supported the Lions ahead of the Springboks.
André Singer, executive producer of the documentary said: "The 'Invincibles' Lions tour of South Africa in 1974 was the most thrilling and momentous tour of all time and you don't have to be a rugby fan to be absorbed by it.
"The players faced an overwhelming political and physical storm and yet came through it bringing home unparalleled victory and finding themselves in the forefront of how sport can become a beacon for political and social change."
The BAFTA-winning Sky Sports rugby team will broadcast every match from this year's Lions tour to South Africa exclusively live and in high definition.
Simon Lazenby presents the action with a commentary and analyst team including five former Lions; Stuart Barnes, Dewi Morris, Will Greenwood, Ieuan Evans and Paul Wallace.
There will also be regular updates, news and views from Sky Sports News reporter Phil Edwards.
THE INVINCIBLES ON SKY SPORTS:
EPISODE ONE: FRIDAY MAY 22, 10PM, SKY SPORTS 2
EPISODE TWO: SATURDAY MAY 23, 9PM, SKY SPORTS 2