The corona will replace the lantern, a small, plain concrete pyramid roof above the Crossing in front of the high altar Photo: PA

The addition – an architectural feature in the shape of a large crown – will complete a section of the church that has been left unfinished for centuries.

The proposals for the corona form part of a major £23 million development of the Abbey which also includes installing a lift on the outside to allow access to a museum.

It is hoped the work will be ready in time to mark the 60th anniversary of the Queen’s Coronation at the Abbey in 2013, with the large crown a symbol of the royal milestone.

The Queen has been briefed on the project, as has the Prince of Wales, who attracted controversy after intervening in the Chelsea Barracks project and succeeded in getting developers to drop the modernist design.

The church, a world heritage site, is a Royal Peculier, meaning the head of the Abbey, the Dean of Westminster, is directly answerable to the monarch.

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’, ‘How absurd’ and ‘How dare you tamper with this great beautiful work we know and love’.

“But what we’re hoping is to demonstrate to people how the Abbey has scarcely stood still in its long history.

“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.

It will replace the lantern, a small, plain concrete pyramid roof above the Crossing in front of the high altar where every monarch including the Queen has been crowned for the last thousand years.

The lantern was damaged during a bombing raid in the Second World War and the current stone slabs date from 1958.

The Westminster Abbey 2020 Vision plans include opening up the London Abbey’s upper gallery known as the triforium to house a museum which will display many historic treasures currently hidden away such as the 14th century Litlyngton Missal illuminated manuscript.

To do so, a lift must be built on the outside in between the north transept and the main body of the church to allow safe access and to comply with disability regulations. The only other route up is a narrow winding staircase.

A spokesman for the Abbey said: “It could be controversial. It’s a 21st century piece of engineering on a medieval building. It has to happily sit within a medieval context.”