A 300-year facelift

Under the programme, St Paul's will be cleaned and repaired inside and out. A new lighting scheme will highlight the building's freshly scrubbed interior, and access will be greatly improved for those with disabilities.

The construction of Sir Christopher Wren's masterpiece began in 1675. It was not until more than three decades later, on 20 October 1708 – the day that Wren turned 76 – that the last of the 70,000 tonnes of Portland stone used in the building's construction was laid on the lantern.

Inside, one of the most challenging areas for the restorers is the spectacular dome scaffold. This revolving platform allows access to the upper part of the inner dome, which was painted by Wren's younger contemporary, Sir James Thornhill. The painting, which shows eight scenes from the life of St Paul, is undergoing a "gentle surface clean", according to a spokesperson for the cathedral.

The restorers will also, controversially, recreate a "missing" section of the painting in the tambour between the Whispering Gallery and the dome. The Victorians painted over the decoration in this area. Under the restoration, artist decorators will use traditional materials to attempt to recreate the original decoration of fluted columns.

Earlier this year, the east front of the building's exterior was revealed after being cocooned behind sheeting for 13 months while the cathedral's own masons undertook stone cleaning and repairs. Restoration of the west front and west steps is due to finish in November. Efforts are now focused on securing funds to complete the cleaning and repair of the rest of the exterior including the badly blackened and damaged south side. Funding permitting, the external programme of cleaning and repair will come to an end in 2008 – just in time for a spectacular birthday party.