In London's Bolivar Hall, campaigners praised Evo Morales's government for the tremendous gains achieved during its first 12 months in power.
Bolivian Ambassador Maria Beatriz Souviron Crespo told supporters: "For the first time in 30 years, Bolivia has no budget deficit, there has been a 30 per cent increase in the minimum wage, while workers have better protection and social security rights.
"Some 170,000 have been seen by Cuban eye doctors and people have been included in decision-making, for which Evo Morales is likely to be nominated for the Nobel Peace Prize."
Cuban ambassador Rene Mujica Cantelar added: "Cuba is no longer isolated and it is our duty to share our achievements in education, health and culture with our Latin American brothers and sisters."
Jorge Martin, international secretary of Hands Off Venezuela and translator for the event, pointed out the similarities between the two countries, especially the "reactionary oligarchic opposition, also backed by the US, who are mobilising against Morales now."
Organisers Bolivia Solidarity Campaign spokeswoman Amanqay Colque declared that "this is a government of change - a government of the people," before Expresion Bolivia got the hall moving to traditional Andean music and dance.
Campaigners then joined a picket outside the Foreign Office called by the Mexico Support Group to protest against that country's "illegitimate" president, who was in London to meet with government leaders.
Chanting "Blair, Brown and Beckett - don't entertain a dictator" and "Oaxacan blood on Calderon's hands," protesters denounced the visit as a "cheap publicity stunt designed to whitewash Calderon's image internationally."
Spokesman Carlos Gonzalez Esquivel explained: "Calderon is a fraudulent and illegitimate president who stole last July's election, officially winning with less the one per cent of the vote.
"There were hundreds of reported irregularities, including ballot-stuffing, vote-dumping and the illegal intervention of former President Fox, elite businessmen and the Catholic church."
Since taking power, Calderon has "viciously crushed" the rebellious social movement in the southern state of Oaxaca, with paramilitary police killing 20 people and imprisoning hundreds more.
National and international human rights groups have reported torture, abuse and rape.
"He's even ratcheted up the price of tortillas, cutting a deal with Wal-Mart so that they can corner the market of this most traditional and basic Mexican food," Mr Gonzalez Esquivel added.
Pointing out that a key condition of the 2000 free trade agreement with the European Union was a clause which requires Mexico to improve its democracy, he called for immediate sanctions.
A petition demanding that Blair exerts "maximum pressure on the incoming government of Mexico to withdraw armed forces from Oaxaca and to release all political prisoners" was handed to Downing Street.
There will be another demo on Monday at 2pm in Whitehall, while Calderon and Blair hold a press conference at Number 10.