The achievement was marked by a rooftop ‘topping out’ ceremony, a centuries old tradition celebrating the highest point of building work being completed.

The ceremony at the top of the Elizabeth Tower (popularly known as Big Ben) was preceded by traditional bagpipe music, and an evergreen bough was attached to the scaffolding by the building and civil engineering company delivering the conservation project, Sir Robert McAlpine Ltd.

Restoring the ‘much loved landmark’

Director General of the House of Commons, Ian Ailles, thanked the team of experts managing the huge task of restoring the Grade I listed building to its former glory, he said: “The steel structure encasing the Elizabeth Tower consists of nearly 24,000 elements, weighs 800 tonnes and has taken just over a year to complete.

“Despite a complex programme and challenging weather conditions earlier this year, we are on schedule, to the credit of all those working on this much-loved landmark and we look forward to welcoming visitors back to the Tower.”

Tom Brake MP, spokesman for the House of Commons Commission said: “This is the most significant programme of works in Big Ben’s 159-year history and this week’s topping out ceremony celebrated it being one step closer to completion. The Elizabeth Tower is an international symbol of democracy and it is vital to preserve it for future generations.”

What stage are the conservation works at now?

Standing at 96 metres tall, the Elizabeth Tower is a focal point of the Palace of Westminster, which forms part of a UNESCO World Heritage site. The world-famous landmark has chimed through the reigns of six monarchs, and is said to be the most photographed building in the UK.

The Elizabeth Tower is now into its second year of conservation. Work includes conserving the stonework and cast-iron roof, as well as dismantling the Great Clock piece by piece with each cog examined and restored.

The four clock dials will be carefully cleaned, the glass replaced and the hands conserved. Whilst the Great Clock and the dials are undergoing conservation, it will be necessary to cover the dials. However, to ensure that the public are still able to see this most important of time pieces, one working clock dial will remain visible consistently throughout the works.

Why are these works so important?

Conservation is necessary for many reasons to prevent the Elizabeth Tower from falling into a state of disrepair, but other reasons for this comprehensive project include:

The ‘topping out’ of the scaffolding represents the latest development in the conservation of the Elizabeth Tower. Earlier this year, the Ayrton Light was removed from the tower to carry out essential repairs, and more recently observers were treated to a striking view of the clock face as the hands were removed to conduct vital repairs.