King of the Gypsy fiddlers

Roby Lakatos, who fuses Hungarian tradition with classical and jazz, is set to dazzle the Proms

In the Grand Mayeur restaurant in Brussels, Roby Lakatos holds court like a pasha. While Hungarian Gypsies play on the stand, he examines a violin, opens fan mail and parcels (ornate jewellery, inlaid chopsticks from Japan), and disappoints devotees by saying he's not going to perform there tonight.

He proceeds to the Ateliers de la Grande Ile, where more Budapest Gypsies are dazzling the diners. Will we hear him now? An opaque frown. Maybe, maybe not, but his 1710 Guarneri stays in its case. Meanwhile – over a vast plate of blinis washed down with vodka – he's happy to tell his story, which starts in the 18th century with the man Liszt and Beethoven called the "Hungarian Orpheus" and "King of the Gypsy Violinists", and from whom Brahms cribbed his Hungarian Dances.

Seven generations separate Roby Lakatos from his ancestor Janos Bihari, but the musical secrets were passed directly down. He himself began playing a sixteenth-size instrument when he was two; at nine he was touring with his father's Gypsy band in the Middle East. "Those were good times for people like us,' he says. "The government was proud of us, and treated us as an elite. My uncle Sandor broke new boundaries by playing classical as well, and the result was hundreds of 78s."

Lakatos was also studying at the Liszt Academy, where at 19 he carried off the top violin prize. Next stop Brussels, and the rest is history, with him becoming a fixture at the Ateliers, where Yehudi Menuhin and Stephane Grappelli came to pay homage. He's about to make his third CD for Deutsche Grammophon. When he plays in Brussels now, Maxim Vengerov, Mischa Maisky and Martha Argerich often attend.

How would he describe what he does? "Gypsy music, with a lot of jazz and classical elements. Though I'm absolutely not a classical musician – everything I do is improvised. I play Bach, but he comes out differently every night." And he has no false modesty: "Until my group came on the scene, Gypsy music had been stagnating. What we do is completely new."

I finally catch him and his band – second fiddle, piano, cimbalom, bass – at a record-company bash, where the music justifies that promise. The whirling sounds blend with the smoky atmosphere to create a madly exciting miasma, in the middle of which Lakatos radiates authority and a massive repose. They're all virtuosi, but Lakatos is beyond compare, with irresistible swing, a huge range of colour and rock-steady intonation no matter how high or fast he plays.

This is the man who will top the bill at the Royal Albert Hall in London next Tuesday. "An Evening of Klezmer and Gypsy Music" is the BBC's description of this Prom, whose other stars are David Krakauer's "Klezmer Madness!" Klezmer is often described as "the Jewish jazz", and it's never been in more vigorous health, drawing on the same spring as Gypsy music and achieving similar effects. The term comes from two Hebrew words, "kley" and "zemer", meaning "vessel of song"; "klezmorim" became the generic term for all Jewish musicians in Eastern Europe. Their music has always fused elements from specifically Jewish contexts – religious observances in synagogue and home – with local styles.

From Greece north via Albania and Romania, the Jewish Gypsy bands who acted as licensed professional musicians developed styles that were virtually interchangeable. Moreover, richer Jews in Hungary would hire Gypsy bands to play for them: much of our information about Transylvanian Jewish music comes from Gypsies who were playing it when the Holocaust wiped out their patrons, and their Jewish fellow-musicians. Meanwhile, the dispersed klezmorim simply carried on in the United States where European pogroms had forced them to leave off. Klezmer is constantly renewed, but always remains itself.

Its influence is steadily invading the classical camp. Three years ago it inspired Itzhak Perlman to make an oddly bewitching CD, Klezmer: In the Fiddler's House (EMI), on which songs and dances are gracefully interwoven.

Lakatos finds klezmer fun, but insists on the superiority of his more ancient Gypsy style. He's got scores of young imitators in Hungary, and he plans to help them. "I want them to have the chance to learn with the best players, as I did." He intends to set up a school.

Prom 33, 14 Aug, 10pm, RAH, London SW7 (020-7589 8212)