U2 member The Edge has warned that the future of Dublin's Clarence Hotel may be in doubt if redevelopment plans are rejected.

A new design would see most of the hotel and five other buildings demolished with a huge glass atrium built over the new structure.

But An Bord Pleanála has begun hearing an appeal by heritage groups who say the redevelopment is inappropriate and affects six protected buildings.

Only the facades of these protected structures would be retained if the plan goes through.

It would mean the virtual demolition of the Clarence Hotel itself, an art deco building from the 1930s, as well as four Georgian buildings to the left and a Victorian building -- Dollard House.

The new design being sought by owners and U2 members Bono and the Edge say it is what is needed to secure the future of the Clarence.

But An Bord Pleanála is hearing a number of submissions against planning permission granted by Dublin City Council

Exceptional circumstances are required to demolish a protected structure and the Department of the Environment says simply having a design of outstanding merit does not qualify.

An Taisce points out the Liffey is a special conservation area and say this design would be more suited to the docklands.

But the design team says the ambition is to make the Clarence one of the top ten hotels in the world.

The hearing is expected to last at least two days.