New footage has shown the progress on the 14,500-tonne bridge which will take the HS2 line under the A46 in South Warwickshire.

The 'box structure' is being built next to the dual carriageway near Kenilworth and will be slid into place during a three-week closure of the road later this year.

The project has taken a "major step forward" as 120 gigantic beams have now been installed, HS2 has confirmed.

The concrete beams, ranging between 13 metres and 24 metres in length were lifted into place using three giant cranes to form an integral part of the structure's top.

A team of engineers worked round the clock to install them in just 14 days.

Three huge cranes are lifting the bridge into place (image via HS2)

Due for completion later this year, the huge box is currently being built on land next to a section of the A46 rather than constructing it beneath the carriageway itself – "avoiding the need for up to two years of roadworks".

With the beams now in place on top of the box, the finishing touches include completing the deck – the flat surface placed on top of the beams – and installing parapets.

In spring, the completed structure will be moved into position under the existing carriageway.

A section of the A46 - between Festival Island (Coventry) and Thickthorn Island (Kenilworth) - will be closed for two weekends next month for the first stage of preparation work.

Dates for the longer three-week closure have yet to be announced.

During the two weekend closures, from 8pm on 7 February to 6am on 10 February and from 8pm on 14 February to 6am on 17 February, HS2 engineers will upgrade road safety barriers, adjust the layout of the central reservation and complete advance drainage works under the carriageway.

Vicki Lee, senior project manager for HS2 Ltd, said: "I'd like to congratulate the entire site team for successfully moving such a large number of beams into place and as we approach the final phase of the A46 box's construction.

"I also thank motorists in advance for their patience as we prepare for the box push in spring and start our initial stage of preparation work during two February weekend closures of the road.

"This will allow us to carry out important work directly on the carriageway that would be unsafe for our workforce to do during live traffic."

Dates for the three-week closure are yet to be confirmed (image via HS2)