Revealed: £21m renaissance of National Gallery

For months it has been hidden from visitors to Trafalgar Square behind giant hoardings.

But on Sunday, the public finally gets to see the first phase of a £21m transformation of the National Gallery in London that restores art to the heart of the building. Eight Renaissance masterpieces, including four by Titian, now dominate the Central Hall, which, after the introduction of humidity control, is being used as a proper gallery for the first time in 30 years. State-of-the art visitor facilities, including an upmarket café, are now housed in what was a disused courtyard and a rabbit warren of corridors in the gallery's East Wing.

The wing also provides a direct entrance from Trafalgar Square, and a second at St Martin's Place to cope with the 4.6 million people who visit the gallery compared with the 200,000 anticipated when it opened in 1837.

Charles Saumarez Smith, the National Gallery's director, said yesterday that muchspace for public use had been opened up, which had put art back in the middle of the building - the first gallery most people saw.

The Vendramin Family and The Death of Actaeon by Titian were two of the greatest paintings of the 16th century. "They now occupy a pivotal place, focusing the visitor's attention on the Italian Renaissance, which is central to understanding the rest of the collection and, indeed, the development of Western art itself.'' If the money was available more unused space could be utilised.

Another seven internal courtyards will be opened to the public on Sunday, which has been called the Annenberg Court in recognition of the $5m (£3m) given by the Annenberg Foundation of Walter Annenberg, the media magnate and former US ambassador in London.

A long-term masterplan to utilise another three courtyards would cost up to £30m more, but would provide a temporary exhibition space triple the size of the galleries in the modern Sainsbury Wing, which are small and have no natural light. But the gallery must still raise more than £3m to pay for the current changes.

Nearly all of the money has been raised privately, including £10m from the Getty families in honour of the late American philanthropist Paul Getty.

The Heritage Lottery Fund rejected a funding application, which Dr Saumarez Smith said did not bode well for future capital developments because the Treasury had said there was no more money available. "Unless we can rely on funding from the Heritage Lottery Fund for capital projects, the development of London's major museums and galleries is going to be highly problematic,'' he said.

Next month, workers begin revamping the original entrance hall and will remove pillars to open it up. Work is due to finish within a year.