Taking down the existing roof will take around four months before Balfour builds a replacement structure under its £41m contract which will take 18 months to complete.

Balfour Project Director Stuart Fraser said: “Technically, this is an enormous challenge. The roof is going to be taken down over the next four months and the lighting panels are starting to come down now.

“There are 14 of them in total, they weigh around 34 tons each.

“There are cables around the tips of the tops of the lighting towers and essentially, what’s happening now is that the towers are tied together on a circumferential cable, which provides stability.

“We have to put in a new network of cables across the venue, and this spider’s web of cables is now in place, which means we can start snipping the circumferential cables and taking the towers down.

“Once the lighting towers are down, we take down the ceremonies’ tripods, which are at the back of the roof.

“They were the structures that were put into place to take the temporary cables during the ceremonies.

“They come down next, and then we embark on taking down the fabric of the roof, and gradually lower down the existing cable-net structure. We’re due to complete late February, early March of next year.

“Then, the deconstruction is complete and we start on the construction of the new roof, which is 84 metres in depth, a very large span roof and one which will cover the entire seating arena.

“That will take a year, we will complete in the Spring of 2015, which gives a period of five months to get ready for the Rugby World Cup preparations.”