VIDEO: Duke and Duchess of Cambridge inside McLaren's new Rotherham site

Prince William and Kate Middleton were shown around McLaren’s Composites Technology Centre (MCTC).

Also opening the site alongside the Royals was The Crown Prince of Bahrain, Prince Salman bin Hamad bin Isa Al Khalifa, who is one of McLaren’'s main shareholders.

The Royal Party was given a tour of the factory floor by Ruth Nic Aoidh, McLaren’s executive director for commercial, and Mike Flewitt, McLaren CEO.

The site aims to be a world leader in innovating lightweight carbon fibre tubs that are integral to the agility and performance of McLaren’s supercars and sportscars.

The royals were shown a completed carbon tub and talked through the process by employees — from the cutting of the carbon fibre cloth, to the forming, pressing, machining and measuring of the final tub.

Prince William was invited to press a button to start the cutting machine by employee Ruth Gawber, and Kate Middleton also started the CNC machine after speaking to apprentice Ian Hutchinson.

The couple also talked passionately with McLaren STEM ambassadors about the work they are doing to encourage school children to get into science and engineering-based careers.

Their Royal Highnesses then joined invited representatives from Rotherham and Sheffield councils, stakeholders and 50 employees for the official unveiling of the carbon fibre plaque.

Addressing the crowd, Mr Flewitt said he was honoured to welcome the Duke and Duchess along with The Crown Prince.

Mr Flewitt said: “Today is an important milestone for McLaren Automotive, for the Sheffield Region and also for the future of manufacturing in the UK.

“In many ways it’s a start-up company — founded just eight years ago, however we are already taking on rivals who have been around 70 or more years.

“That’s been possible because of the long-term shareholders who understand our vision, and are passionate about our people and products.”

Mr Flewitt said McLaren’s first factory opened in Woking seven years ago and now over 90 per cent of his products were exported worldwide.

He paid tribute to the company’s founder — motor racing driver Bruce McLaren — and said the “exceptional facilities” would help to make the “visionary’s” dream come true.

Mr Flewitt said the £50m Rotherham site was the firm’s second factory and a "worthy addition to the McLaren group".

He said: “We already have over 50 talented, dedicated pioneers working here in the region, many drawn from the local area, many met the Royal Highnesses this morning.”

Mr Flewitt said that by 2020 the Advanced Manufacturing Park-based site would employ over 200 people, bringing McLaren’s total workforce to 3,500.

The Rotherham site “was more than simply a factory”, said Mr Flewitt adding: “Although manufacturing is an important part, it’s an innovation centre, a place where new technology will be developed.”

The Duke and Duchess and The Crown Prince joined Mr Flewitt on stage to unveil the plaque.

The royal party were the first guests to sign the visitors’ book at the end of the hour-long tour.