Next spring, New London Consort and Jonathan Miller, the team who brought us the 2004 Brighton Festival sell-out L'Orfeo, will tour a brand new production of Purcell's Dido & Aeneas, reinstating it to the length of a full opera.

Before then the Consort, led by Philip Pickett, will be giving two semi-staged performances in order to test the newly reconstructed score. One is in a month's time at the Cite de la Musique in Paris. The world premiere is tonight as part of the Brighton Festival.

According to Pickett, Purcell was "the greatest setter of English words to music". But the composer only wrote one true opera and this, as was common in the period, was chopped up into four parts and inserted between the acts of an adaptation of Shakespeare's Measure For Measure.

This performance of Dido & Aeneas took place in 1700 at the Lincoln's Inn Fields Theatre, with additional text by Charles Gildon and additional musical numbers by the theatre's musical director, John Eccles.

What Pickett's team have done is to reconstruct the 1700 version (the earliest full scores were copied as late as the second half of the 18th century), with the 28-strong ensemble, including slide-trumpets, kettle-drums, oboes, recorders, serpent, bassoon and doublebass.

He calls it "the new mega Dido". "We're pretty sure the original Dido involved just a string band, with a harpsichord or lute," says Pickett, one of the country's foremost specialists in period music. "But we know that in the theatre in 1700, the band was much more interesting. It even had a serpent, which sounds like a tuba but with finger holes like an oboe.

"John Eccles seems to have had a great penchant for the things and included them when the witches appeared to give a terrifying low, rumbling sound. So we've added a serpent. They're very rare - in my opinion there's only one guy in England who can play it properly. And of course he's playing in this performance." Led here by Julia Gooding as Dido and Michael George as Aeneas, Purcell's opera is based on book four of Virgil's Aeneid, in which Dido, queen of Carthage, falls in love with Aeneas, who has dropped anchor in her realm following his people's defeat in the Trojan War.

The opera adds in a coven of witches who, out of hatred for Dido, remind Aeneas that he is fated to be the founder of the Roman Empire. When Aeneas leaves, Dido is so heartbroken she commits suicide.

"It's incredibly emotionally moving and dramatic," says Pickett. "The witches bits are quite fun. They cackle and make spells, and because they're in a cavern there's a wonderful echoed chorus. Then there's a bit for debauched sailors which sounds like the orchestra are plastered. We have the string players sliding about all over the place."

As for the "semi-staging", there will be no costumes or set but the opera will be performed Proms-style, with the concert's hall's front stalls seats removed.

"There will be processions, interaction between characters, people singing in the audience and Mars, I hope, appearing from up in the gallery," says Pickett. "Imagine someone singing within 12 inches of you. It'll be electric."

  • Starts: 8pm Tickets: £7.50-£25