Having won the all-around, vault and beam golds at the Tokyo 1964, Caslavska completed her set in Mexico as she retained her all-around title by winning the vault again, and the asymmetric bars, as well as taking joint gold in the floor exercises.

The latter event was where her crucial action occurred. Originally adjudged as winner, she was going up to receive her medal when it was announced that the score of the Soviet Union’s Larisa Petrik had been upgraded and the title was to be shared.

When the Soviet Union’s national anthem was played, Caslavska stood with her head down and turned away in a silent but unmistakable protest.

Earlier in the Games after another very controversial judging decision that had cost her gold on beam – with Soviet rival Natalia Kuchinskaya taking the title - Caslavska had also turned her head down and away during the playing of the Soviet national anthem.

Upon her return to a country under Soviet rule she gave her four golds to the Czech leaders of the “Prague Spring” - the doomed attempt to liberalise the Communist regime that had been established by a coup d’etat in 1948.

The podium demonstrations had already settled her fate, and after that defiant homecoming there was no chance of any other outcome. Caslavska was shunned by the Establishment for more than 20 years, losing her job and her right to travel, until the changes brought about by the fall of the Berlin Wall re-established her in triumphant fashion…

In making that point on the podium, Caslavska had defied not only the Soviet ruling system but the International Olympic Committee (IOC).

Chapter five of the Olympic charter insists: “No kind of demonstration or political, religious or racial propaganda is permitted in the Olympic areas.”

She was not the first, or the last Olympic athlete to transgress.

The 1906 Intercalated Games have subsequently been annulled as an official Olympics by the IOC, but they were successfully staged by the host of the first modern Olympics, Athens, and attracted 854 athletes.

Among this number were three disgruntled Irishmen who had been entered by their home country but were then left in limbo when the Games rules were changed so that only athletes nominated by National Olympic Committees were deemed eligible.

Ireland, still officially part of United Kingdom, had no NOC at that time so the three athletes - John Daly, Con Leahy and Peter O’Connor – were subsumed into the British team.

All three had originally received green blazers and caps with gold shamrocks on, and an Irish flag with the wording Erin Go Bragh (Ireland for Ever).

The blazers and caps were put to good use by the Irish trio in defiance of regulations over their team colours. And when O’Connor took silver in the long jump (after his best and potentially gold-winning effort had been controversially ruled out) his reaction on seeing the Union flag being raised at the medal ceremony was to shimmy up the flag pole – with Leahy standing guard at its base – and wave the third green item that had been given to him before the arguments began.

Later in the Games, O’Connor and Leahy took gold and silver respectively in the triple jump (then known as the hop, step and jump) and asked officials to raise two Irish flags for them. When that request was refused, they paraded around the stadium bearing their own flags.

O’Connor was among numerous athletes who boycotted the London Olympics two years later in protest at the UK’s continuing refusal to grant Ireland its independence. But those 1908 Games had more than their share of athlete demonstrations.

On the opening day, following the practice introduced at the 1906 Games, teams paraded behind their national flags. Since Finland was part of the Russian Empire, its team members were expected to march under the Russian rather than the Finnish flag. Many of them chose to march separately with no flag of any kind.

And in another political gesture, Sweden’s team members refused to take part in the Opening Ceremony as their national flag had not been displayed with all the others around the rim of the White City stadium.

Although the flag of the United States was also missing from the general display in the stadium, the members of the US team did take part in the Opening Ceremony. However the US flag bearer, Ralph Rose, refused to follow the pattern of all the other teams in dipping the flag to King Edward VII as he sat in the Royal Box.

Rose’s colleague Martin Sheridan was apocryphally quoted as supporting the gesture with the following statement: “This flag dips to no earthly king.” Lofty rhetoric indeed, but research has since shown this quote was first reported in 1952, more than 24 years after Sheridan’s death.

In the context of the 1936 Berlin Olympics, which the rising force of the Nazi party attempted to use as a demonstration of Aryan racial superiority, the behaviour of home long jumper Luz Long stands out as not only personally honourable but politically courageous also.

The 1936 Olympics are primarily remembered as those in which Jesse Owens, the black sprinter and jumper from the United States, claiming four gold medals. Had it not been for Long’s friendly intervention in the long jump qualifying, however, that total might have been three.

As Owens, who less than three months earlier had set a world record of 8.13m that would last for 25 years, prepared for his third and final attempt after fouling out twice, Long advised him to put his starting mark back a few centimetres to be sure he didn’t go over the take-off board line. Owens only needed to get a qualifying mark of 7.15. The American took the German’s advice and qualified for the evening’s final with 10cm to spare.

After Owens had won gold in an Olympic record of 8.06m, after a see-sawing competition which has seen Long leading with 7.87, the German was the first to congratulate his opponent and after posing for photos together they walked arm-in-arm to the dressing rooms.

Owens later commented: "It took a lot of courage for him to befriend me in front of Hitler...you can melt down all the medals and cups I have and they wouldn't be a plating on the twenty-four carat friendship that I felt for Luz Long at that moment."

It was at the Mexico Games of 1968, however, that the most famous individual athlete protests in Olympic history took place.

After US athletes Tommie Smith and John Carlos had taken gold and bronze respectively in the 200m – where Smith had set a world record in the rarified atmosphere of 19.83sec – they turned the medal ceremony into a profound political statement of solidarity which effectively ended both of their athletics careers as it drew a furious reaction from, principally, the IOC, but also from many of their fellow Americans.

The Games took place to a background of volcanic political tensions around the world. More than 300 students had been shot dead in Mexico City itself on the eve of the Games as they protested against their Government. In South America, millions of black people were still suffering under the apartheid regime that had seen the country banned from the Olympics in 1960.

In the United States, Martin Luther King Jr, a powerful leader of the African-American Civil Rights Movement, was assassinated six months before the Games began and many protestors against racial inequality were working within the Black Power movement, which rejected the non-violent tactics which Luther King had advocated.

As they took to the podium, Smith and Carlos were both shoeless but wearing black socks – something they later explained was to represent black poverty. Smith wore a black scarf around his neck to represent black pride, Carlos had his tracksuit top undone to show solidarity with all blue collar workers in the US and also wore a necklace of beads which he subsequently described as being “for those individuals that were lynched, or killed and that no one said a prayer for, that were hung and tarred.” Each wore a single black glove, which they raised in a fist, with bowed heads, as the Star Spangled Banner anthem played.

All three on the podium, including Australian silver medallist Peter Norman, who had been a critic of Australia’s former White Australia Policy, wore Olympic Project for Human Rights badges. He had suggested that the two US athletes take one glove each after Carlos had accidentally left his pair in the Olympic village.

As they left the podium they were booed by the crowd. Smith later said, "If I win, I am American, not a black American. But if I did something bad, then they would say I am a Negro. We are black and we are proud of being black. Black America will understand what we did tonight.”

The gesture raised boos from many of the spectators. The US National Olympic committee was leaned upon by the IOC – whose American President, Avery Brundage, later referred to the incident as “the nasty demonstration against the American flag by negroes” – to suspend the athletes and send them home.

Both received death threats, and Carlos’s home was attacked.

Although no formal action was taken against Norman, his actions were resented by many in his home sporting establishment, and he was controversially left of the 1972 Olympic team, retiring soon afterwards.

When Norman died of a heart attack in 2006, Smith and Carlos acted as pall bearers and Carlos recounted the conversation they had before going out for the medal ceremony.

He said he and Smith had asked Norman if he believed in human rights, and he had said he did. He said they asked him if he believed in God and Norman, who came from a Salvation Army background, had said he believed strongly in God.

"We knew that what we were going to do was far greater than any athletic feat,” Carlos recalled. “Peter said, 'I'll stand with you'.”

Carlos added that he had expected to see fear in Norman's eyes, but didn’t. "I saw love,” he said.

US athletes were warned in Mexico: “A repetition of such incidents...would warrant the imposition of the severest penalties at the disposal of the US Olympic Committee.”

But subsequent protests of varying degrees took place. After Lee Evans had led home a US clean sweep in the 400m, all three winners wore black berets to their medal ceremony. Bob Beamon, who broke the world record in the long jump, wore black socks pulled up high at his ceremony, while fellow US bronze medallist Ralph Boston went barefoot, commenting: “They’re going to have to send me home too.” He was not sent home.

As a postscript, the US women’s 4x100m relay team publicly dedicated their own gold medals to Carlos and Smith.

It was less than a week after the men’s 200m that fate - in the form of a controversially amended result - created up the opportunity for Caslavska to make her feelings clear about the newly installed Soviet regime in her country.

Six months earlier, she had been among many prominent Czechs to sign the protest document against Soviet-style Communism, “Manifesto of Two Thousand Words”, along with the retired multiple Olympic champion Emil Zatopek.

Both would pay heavily for that statement of committment in years to come as they lost all official standing, with Zatopek even being moved to work in a uranium mine at one point.

As David Wallechinsky’s Complete Book of the Olympics records: “On August 21, Caslavska was at a training camp in Moravia when Soviet tanks rolled into Prague. Warned by friends that she was in danger of arrest, she fled to the small town of Sumperk in the Jeseniky Mountains.

“With the Olympics only two months away, Caslavska was in hiding, keeping in shape by swinging from tree limbs and practising her floor exercise in a meadow.”

Caslavska, who also worked on her strength by lifting bags of coal, later recalled: “A tree that had fallen became my beam. I ran up to vault on a forest path. I turned the forest into a gym.”

A last minute change of heart by the Czech regime allowed her to join the rest of the team in Mexico City in time for the opening Olympic ceremony on October 12. Even the hardliners could not refuse the likely prospect of further glory thanks to a woman who had won three of Czechoslovakia’s five golds at Tokyo 1964 and had won every major competition in the intervening years.

But on her return she was internally exiled for more than two decades. It was not until the then IOC President, Juan Antonio Samaranch, insisted upon being able to present her and Zatopek with the Olympic Order that her stock began to rise with the Czech authorities, and she was allowed to return to coaching at a club level.

When the Communist regime was dismantled in Czechoslovakia in 1989, Caslavska was restored to the mainstream of national life by the new President, Vaclav Havel, and served briefly as President of the Czech National Olympic Committee, joining the IOC in 1995.

Caslavska’s personal life was as much a thing of light and shade as her sporting career. While still at the Mexico Games she married Tokyo 1964 800m silver medallist Josef Odlozil in a ceremony attended by thousands in Mexico City Cathedral. Later that year she was chosen as Sports Woman of the Year and came second to Jackie Kennedy in the Woman of the Year vote.

The couple divorced in 1987 and six years later Odlozil died as a result of an altercation in a bar involving his 19-year-old son Martin, who was subsequently jailed for four years but was granted a controversial pardon by Havel in 1997.

Caslavska suffered a long period of depression during this time, but returned to her sport before she died of pancreatic cancer by coaching younger gymnasts.

Four years after the landmark protest of Smith and Carlos in Mexico, two other black American athletes, Vince Matthews and Wayne Collett, respective gold and silver medallists in the 400m, staged what many believed to be a protest with a similar theme at their ceremony.

During the ceremony both men talked to each other, shuffled their feet, stroked their chins and fidgeted while the US national anthem played. Leaving the arena after the ceremony, Collett gave a Black Power salute.

An Associated Press report described the actions as “disrespectful”, adding:

"Collett, bare-footed, leaped from the No. 2 tier to the No. 1 stand beside his teammate. They stood sideways to the flag, twirling their medals, with Matthews stroking his chin. Their shoulders slumped, neither stood erect nor looked at the flag. ... As whistles and catcalls continued, Collett raised a clenched fist to the crowd before entering the portal of the dressing room.”

In an interview after the medal ceremony with the American Broadcasting Company Collett said the national anthem meant nothing to him, explaining that he had felt unable to honour the anthem because of the struggle faced by African Americans within US society. "I couldn't stand there and sing the words because I don't believe they're true,” he said. “I wish they were.”

Both men were banned from future Olympic competition by the IOC.

Political events in Russia in the run-up to the 2014 Sochi Winter Games provoked notable protests by competitors.

Ukrainian Winter Paralympians staged a symbolic protest at the opening ceremony of the Sochi Games, with all but one athlete boycotting the athletes' parade in protest at Russia's incursions into the Crimea.

Despite the tension between the two countries, Ukraine remained to compete in the Paralympics, but made a point by sending just one athlete around the Fisht Stadium to represent their 31-strong team.

The solitary flagbearer, Nordic skier Mykailo Tkachenko, was greeted with loud cheers.

Before the start of the Winter Olympics there had been a storm of international protest over the law passed in Russia in June 2013 which banned the distribution of “propaganda of non-traditional sexual relationships” among minors. The law was seen widely in the West as a means of clamping down on public displays of lesbian, gay, bisexual and transgender symbols and culture.

During the Games, after the slopestyle event qualifying, Dutch competitor Cheryl Maas, who is openly married to another woman, raised her glove bearing a unicorn and a rainbow – the symbol adopted by LGBT supporters - to the cameras.

The snowboarder had reportedly previously criticised the decision to hold the Games in Sochi, stating, "With the choice of Russia, the IOC is taking a step back in time."