A Scottish manufacturer has signed a deal to build vehicles for the world's biggest producer of electric buses, which could be worth nearly £2 billion.

Alexander Dennis Limited (ADL), based in Larbert, near Falkirk, has entered a joint venture agreement with Chinese firm BYD on the back of the UK state visit by Chinese president Xi Jinping.

The initial contract will see the manufacture of 200, 12-metre (40ft) single deck buses a year, representing turnover of around £660 million over the next 10 years.

They are also in discussions to extend their alliance to include double decker buses which could triple the deal to almost £2 billion.

The contract was signed by Wang Chuan-fu, founding chairman of BYD, and Colin Robertson, chief executive of ADL.

Mr Wang said: "Working with top industry partners such as ADL will enable us to speed up acceptance of our vision for fully-electrified public transport systems that can make a major contribution towards the clean air challenges facing cities around the world.

"ADL's know-how and local market experience in the UK, combined with their global expertise in the double deck sector and our class-leading knowledge of electric technology, creates the perfect platform to jointly develop a range of cost effective, emission-free vehicles to suit every requirement."

Mr Robertson said: "This is the start of an exciting journey with enormous potential and we are delighted to be working with BYD.

"Their expertise in electric vehicle technology is second-to-none, while we have a global reputation for robust, reliable, high performance vehicles that deliver what they promise - and are backed by world-leading parts and service support, both in the UK and international markets.

"The combined strengths of BYD and ADL create a powerful new alliance and I look forward to our business relationship flourishing in the years ahead. It is a fine example of British-Chinese co-operation and two innovative companies working together to create cleaner, greener transport solutions.

"It is also important to recognise that it is initiatives like this that help us support 2,500 ADL jobs and a further 1,500 in our build partnerships around the world."