According to the Foreign Office, which under Robin Cook claims to have made "ethics" central to its deliberations, Mrs Plavsic is being honoured with an official greeting from minister Tony Lloyd because she is "moderate". "We want to give her position a bit of a boost," a spokes- man was quoted as telling Reuters news agency.
Bosnia's Muslims - those who survived the slaughter organised by Mrs Plavsic and her two colleagues, Radovan Karadzic and Nikoila Koljevic, which culminated in the massacre of Srebrenica's male inhabitants almost exactly two years ago - remember Mr Lloyd's guest as one of the most terrifying of all their persecutors, a powerful-looking, elegantly dressed, heavily perfumed lady, who seemed to exult in their annihilation.
They remember, as Mr Cook's officials apparently do not, how in April 1992 the Serb paramilitary boss Zeljko Raznjatovic "Arkan" stormed the small, mostly Muslim town of Bijeljina in north-east Bosnia, butchering many of the inhabitants, and how Mrs Plavsic rushed to the town and - after inspecting Arkan's grisly handywork - gave him a rapturous kiss.
Mrs Plavsic, far from being a "moderate" in the Bosnian Serb hierarchy, made such bloodcurdlingly racist speeches throughout the Bosnian war (her favourite topic was the biological differences between Serbs and Muslims) that even President Slobodan Milosevic of Serbia became disgusted, or at any rate, embarrassed.
Using his journalist wife, Mirjana, as was often his practice, to express in print what the secretive leader really thought, he pronounced Mrs Plavsic "a Nazi" and compared her to Dr Mengele in the weekly magazine Duga - this, after Mrs Plavsic had unburdened her thoughts to a Belgrade newspaper saying it was her "dearest wish to see the Drina valley cleansed of Muslims". She went on: "I wish them no good, though to get my peace, I'll have to give them something, so that they do not disturb me."
Other famous Plavsic comments include how the Muslims were lucky that the Serbs were shovelling them into crowded ghettos because they were Orientals - and those people enjoy living on top of each other.
The Foreign Office says Mrs Plavsic deserves "a bit of a boost" because, unlike Mr Karadzic, she is willing to deliver on the November 1995 Dayton peace deal which was designed to heal the division of Bosnia and rebuild the country.
In fact, when Madeleine Albright, the US Secretary of State, recently toured Bosnia and Croatia, warning Washington would get tough on delivering up UN-indicted war-crime suspects to the Hague tribunal, Mrs Plavsic replied by threatening "massive civil and military unrest" if any attempt was made to apprehend either Karadzic or the man behind the Srebrenica horrors, General Ratko Mladic.
And during the Bosnian elections in September last year, after which she became president of the Bosnian Serb statelet, she wowed the crowds in the Serb-held part of Dobrinja outside Sarajevo by telling them Mr Karadzic was "our Karageorge", thus likening him to the hero of the 1804 Serb uprising against the Turks. "You heroic people, you showed the world we can never live with them [the Muslims], even in peace!" she shouted.
As Bosnian Serb president she presided over the demolition of the remains of the celebrated 16th century Ferhadija mosque in Banja Luka, a fitting epitaph to the work of "ethnic cleansing" which she has consistently espoused.
"It's so ironic she is being presented as a moderate because for much of the war she bitterly opposed Karadzic, whom she saw as a weak-kneed moderate," says Tim Judah, an expert on Serbia and author of The Serbs: History and Myth.
Serbian liberals feel just as dismayed by the news that British officials are welcoming a woman they feel has shamed their nation. "She is a racist, and an extreme racist" says Sonja Biserko, of the Helsinki committee for human rights in Serbia, "and as big a war criminal as Karadzic. She spent the whole war touring the battlefields stirring up the troops."