'Breathtaking' was the verdict of Oxford University curator Jeffrey Hackney after the Sheldonian Theatre’s ceiling was fully restored after four years of work.

The 32 panels in the ceiling were taken down in 2004 to allow essential repairs at the historic building in Broad Street.

It was then discovered that the panels, showing Truth descending upon the Arts and Sciences to expel ignorance from the University, were also in need of repair.

Following conservation work, a project to put the panels back in place began earlier this year and has now been completed.

The restored ceiling fresco was first unveiled at a reception yesterday and will be seen by the public at a degree ceremony today.

Mr Hackney, Oxford University’s chairman of curators, said: “I have been very impressed with the good nature and efficiency of the team who have worked together all summer under some fairly intense pressure to get the ceiling open in time for the degree day.

“I think there will be much drawing in of breath when people see the restored ceiling for the first time.”

Mr Hackney added that new concealed lighting was due to be installed in 2010, which would make the ceiling an even more spectacular attraction. The panels, featuring oil on canvas, were painted by King Charles II’s court painter Robert Streater.

The London-born painter specialised in large-scale architectural and decorative paintings.

The panels have been carefully restored, with their linings replaced and holes in the canvases fixed.

Following the discovery of two time capsules, the university has hidden a 21st century capsule behind the panels to document the latest restoration project.

One capsule dated 1901 contained an old pair of trousers plus a note from their owner, picture liner Frank Morrill.

The note, dated March 6, 1901, read: “Hope you enjoy yourself when you have found this valuable treasure – I expect I will have fed the worms by that time.”

The Sheldonian Theatre is a Grade I-listed building and the main assembly room of the university.

It is also the regular meeting place of Congregation – the 4,000-strong parliament of dons which controls the university’s affairs.