Foreign Office Minister Jeremy Browne's accidental revelation that British troops are co-operating with the Colombian armed forces ought to sound the alarm bells.
British forces have a far from clean record in Iraq and Afghanistan, not to mention earlier in Ireland, but the US-trained and supplied Colombian military is up to its neck in civilian blood.
Colombia is the most dangerous country in the world to be a trade unionist, with dozens killed annually by death squads, including army personnel, paid for by big business and agricultural interests.
While most crimes go unpunished, some trials have taken place since current President Juan Manuel Santos, a former defence minister, took over from Alvaro Uribe.
Uribe's close political ally Jose Noguera, who was head of the DAS secret police, was jailed for 24 years on September 14 for involvement in three murders carried out by paramilitary death squads.
Three months earlier, Colonel Luis Fernando Borja was sentenced to 21 years in prison over the killing of 57 civilians.
Colonel Borja, who had his sentence halved from 42 years for coming clean, admitted that his unit had murdered the civilians and passed them off as Farc liberation movement guerilla fighters.
Colombia's oligarchy, transnational capital, the army and DAS have worked together for years to eliminate political opponents - trade unionists, peasant leaders, environmental campaigners, teachers and community activists - and to portray their victims as armed rebels.
President Santos insists that he has put an end to this widely practiced ploy, known as "false positives," which was encouraged by rewarding poorly paid soldiers with bonuses for the number of guerilla "kills" they booked.
The attorney-general's office is at present investigating more than 1,400 cases of extrajudicial killings throughout Colombia.
Our government may give President Santos the benefit of the doubt over the conduct of the armed forces when he was defence minister. He certainly admitted in November 2008 that extrajudicial executions had taken place, but he pledged to rectify this situation.
High-ranking military officers, including three generals, were sacked, although the charges against them described administrative failures, irregularities in reporting enemy casualties and operational results rather than conspiracy to murder.
Santos claimed in March that the "issue of false positives has gone," declaring that "there has not been a single false positive case since October 2008."
However, the question arises as to whether Santos's actions are as good as his words.
Colombian NGO Cinep (the Centre for Investigation and Popular Education) gave details earlier this week of a further 961 alleged false positives, some having taken place as recently as June of this year.
Cinep said that research for its Debt to Humanity special report showed that, while some of the cases went as far back as 1988, nine had occurred since Santos took up the presidency.
It details instances of teenage boys being killed by the army's Brigade 30 before their corpses were dressed in Farc guerilla uniform and had guns placed alongside them before they were photographed.
The government should learn the lesson of Labour former foreign office minister Kim Howells, who was happy to pose for smiley pictures with a unit of the Colombian army only to learn later that they were deeply involved in the false positives murder programme.
It should end all co-operation with Colombia's armed forces until Bogota takes human rights for working people seriously.