Plans have been announced for the first major building work at Westminster Abbey for 250 years.

The proposals would see a corona – an architectural feature in the shape of a large crown – sit on the roof of the historic structure.

The plans form part of a major £23m development of the Abbey.

It is hoped the work will be completed by 2013 – a year which will mark the 60th anniversary of the Queen's Coronation at the Abbey.

The Dean, the Very Rev Dr John Hall, who has been spearheading the plans, said: "It's extremely exciting. It's the first major development here for a long time.

"There will of course be some people who say 'Don't change our skyline after all this time'."

He added: "I don't think we would go against the bulk of public opinion. If there was an adverse reaction, I expect we would drop it."

If the plans are supported following public consultation, architects will be asked to enter a competition, overseen by the Royal Institute of British Architects, to design the corona.

The Westminster Abbey 2020 Vision plans also include opening up Westminster Abbey's upper gallery – known as the triforium – to house a museum which will display many historic treasures currently hidden away.