An extraordinary thing happened on the South Bank in London yesterday. After the fiascos of Wembley Stadium, the Scottish Parliament and the Millennium Dome, a landmark publicly funded building project was completed on time and almost on budget.

The renovation of the Royal Festival Hall will probably end up costing £115 million, within 5 per cent of the original budget, of which £105 million has already been raised. The remaining funds have been borrowed, so the shortfall will not prevent the Grade I listed concert hall from staging a spectacular reopening as scheduled after two years as a building site.

At dusk on June 8 a candlelit barge carrying 250 singers will float down the Thames, opening a 48-hour festival of continuous free music, dance, film and visual arts involving 18,000 performers.

Then, on June 11, the four orchestras resident on the South Bank – the London Philharmonic Orchestra, the Phil-harmonia Orchestra, the London Sinfonietta and the Orchestra of the Age of Enlightenment – will play together for the first time at the venue’s opening concert, culminating in all 250 musicians romping through Ravel’s Bolero on the same stage.

Critical ears will be trained on the room’s notorious acoustics, which have been the bane of audiences and performers since the Royal Festival Hall was built – hurriedly and cheaply – for the Festival of Britain in 1951.

More than £40 million of the total project cost has been spent on a new auditorium. It looks very like the old one, but a new wave-patterned ceiling, heavier than the original and geared towards producing a much fuller sound, is now in place. The 2,788 seats by Robin Day have been reupholstered and given an extra few inches of leg room.

On the walls the elegant French elm panels have been carefully replaced but they are now backed with densely packed gypsum where once they rattled like drumskins and absorbed sound like sponges.

“The sound is much better,” Vladimir Jurowski, the conductor of the London Philharmonic Orchestra, said between rehearsals yesterday. “It is much clearer and richer than it used to be.”

Lord Hollick, the chairman of Southbank Centre, which incorporates the Queen Eliza-beth Hall, the Purcell Room and the Hayward Gallery, was optimistic that the remaining funds would be raised quickly, even though only £1 million has been pledged since January. “Now that we have got a wonderful building to show off we are feeling very confident,” he said.

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