"The desire of sex rages within the chaste contours of the tango figures; the bodies do not touch yet they are joined. So intense is the current within the man and the woman that it leaps in the air and copulates them."

Waldo Frank, US writer.

When the tango swept the world in the 1920s its arrival in Ireland was greeted by clerical outrage and public approval, with bishops suggesting that offenders seek confession after a night in the ballroom.

Ms Mary Tomasini-Whelan, whose parents are credited with bringing the dance to Ireland in the 1920s, acknowledged the danger. "Tango is a dance where you have an affair with the other person for four minutes," she said, speaking at her dance school in Parnell Square, Dublin, where she still gives lessons after 50 years on the floor.

Early in 1914, two members of the Roman nobility demonstrated the tango for Pope Pius X, who was not impressed, describing it as "the barbarian contortions of Negroes and Indians". While the Charleston celebrated life and the jitterbug hinted at rebellion, the tango, derived from the Portuguese tangere, to touch, celebrated self-pity and nostalgia.

The dance was born in Argentina, via the local milonga and African Candombe rhythms, first danced by the compadritos (tough guys) who frequented bars and brothels in Buenos Aires at the turn of the century.

The street toughs danced with each other while waiting their turn with the women, the moody ballads powered by the bandeon, a small accordion brought from Hamburg by German sailors, while violins, flute and guitars eventually filled out the sound.

The world of the tango lyric was a hostile one, its outlook pessimistic, prompting Argentina's best known writer Jorge Luis Borges to criticise the lyrics for "indulging in loud self-pity while shamelessly rejoicing in the misfortunes of others".

At first glance the tango resembles a contortionist nightmare, with bodies interlocked, legs entwined, dancers looking the opposite way to each other, guided by touch. This sensory dependence was highlighted in Martin Brest's film Scent of a Woman, (1992) where Al Pacino, a blind ex-military officer, danced a perfect tango.

"There are no mistakes in tango," said Pacino's character, "not like life. If you get all tangled up you just tango on."

The appearance of a tango in a big film or a stage show invariably sends dozens of converts to Ms Tomasini-Whelan's classes. Asked how the stiff inhibited Irish nature took to it, she had no hesitation. "The sense of the exotic," she said. Back in the 1950s, her dance partner was her brother George and together they finished among the top 24 dancers in the World Ballroom Dancing championships of 1959.

In an issue of the Irish Ballroom magazine, dated 1925, the editorial outlined steps to follow in the newly arrived tango. "The girl must keep a soft hip movement and the man's right hip must be slightly advanced, pressing in fact against his partner's left hip." The magazine also explained how the "tango woman" should behave and look. "She will be rather dreamy and low-voiced, reflecting the sighing, philosophic quality of the music", wearing a dance frock with a flared skirt, 2 1/2-in heels and hair "inclined to curl rather than to wave".

This reporter attended a weekly class organised by the Dublin Argentine Tango Society upstairs in Mother Redcap's, in the centre of Dublin.

By 7 p.m., 15 couples were shyly limbering up as a tango played in the background and two Argentinean teachers observed their charges. Posture is crucial, with both partners facing each other chest to chest, forming a downward V shape.

"You must begin with an embrace," began Gustavo Porter, an elegant patient teacher, who hugs his partner Monina Paz, before gliding around the floor with extreme grace. The steps speeded up, a hint of waltz, a hint of ballet, as she wrapped her leg around his, before they paused to order the Irish volunteers onto the floor. "Stop thinking and just feel the music," said Gustavo, warning against the temptation to watch your feet rather than feel the rhythm.

The Argentineans followed each couple across the floor, straightening backs and adjusting wrists. It was beautiful to watch and after an hour of beginner's steps, everyone had grasped the basic step.

It's hard to believe that the tango, the quintessential symbol of Argentinean pride, was once the scourge of officialdom, denied and repudiated until the 1930s, its low-life brothel origins upsetting the elite. "It is not really Argentinean," argued one Argentinean diplomat in the 1920s, "but a hybrid of mixed blood, born in the slums."

One Buenos Aires newspaper lamented at the time that watching the tango, "one would think one was seeing a couple of Arabs under the influence of opium".

It was tango fever in Paris which opened the doors to widespread acceptance at home. France adopted the dance as its own, forming tango clubs, tango tea parties, even a tango train, which carried revellers from Paris to Deauville in 1913.

The tango is considered wholly machista yet observers argue that the embrace is one of equals, a hug of mutual force. As the bodies unravel, the male is not dominant, he is the mirror of the female. In the early years, men danced with men, as women were in short supply in the immigrant nation. "The tango is man and woman in search of each other. It is the search for an embrace, a way to be together, when the man feels that he is a male and the woman feels that she is a female, she likes to be led, he likes to lead," said Juan Copes, a leading tango choreographer.

The Dublin Argentine Tango Society, formed last October, has gone from strength to strength, recently celebrating a tango asado (Argentinean barbecue, much more than a meal, a rite of cultural passage), in Longford town, attended by more than 100 guests, including Argentina's ambassador who opened the proceedings.

The word is spreading fast with regular classes in Dublin and Belfast, a new one opening in Kilkenny as the heady tango mixture of sex and chess bewitches a new generation of Irish dancers. For more information on tango classes, contact Rosemary or John at (01) 494 5577.