ALEXANDER Dennis has secured an order for up to 400 buses from Canadian transport company Metrolinx, which is believed to be worth about £300 million.

Most of the engineering and design on the double-decker vehicles will be carried out in the UK, including at the Falkirk and Larbert sites which employ about 900 people.

However the deal in Canada will see Alexander Dennis set up a new chassis assembly facility close to Ontario, which is expected to employ about 30 people when fully operational.

The contract involves the supply of 250 double-decker buses over the next five years while Metrolink, the government of Ontario's transportation authority for the Greater Toronto and Hamilton area, has the option to purchase a further 150 vehicles.

The ultra-low vehicles will be able to access four terminals that cannot presently be reached by traditional double-deckers as a result of height restrictions.

About 125 Alexander Dennis vehicles are already in use across the area.

Colin Robertson, chief executive of Alexander Dennis, said: "This initiative is the result of a seven-year business relationship with Metrolinx that has gone from strength to strength.

"It involves a multi-year, exclusive agreement for the supply of double-deck buses and marks a milestone for [Alexander Dennis]."

No financial terms of the deal were released but transport industry sources suggested the value was close to £300m.

Metrolinx president and chief executive Bruce McCuaig said: "These buses represent the future of our bus fleet and set a new standard for the service we provide.

"Their lower floors will allow customers with limited mobility to board with ease, and their lower height will allow us to bring double-decker service to all of our routes."

Building work on the new manufacturing facility is expected to start in the middle of next year, with the first new buses arriving early in 2016.

Mr Robertson said: "We look forward to becoming a fully-fledged contributor to the local economy, creating jobs and extending our supplier network."

The establishment of that base is also expected to help Alexander Dennis expand further across North America.

It has vehicles operating in cities such as New York, Washington DC, Las Vegas, San Francisco, Vancouver and Ottawa.

Robert Davey, Alexander Dennis's group commercial and business development director, said: "This latest order will see the double-deck establish itself as the backbone of the bus fleet in the Greater Toronto and Hamilton area and provide the springboard for [us] to expand further in Canada and the USA."

Alexander Dennis, which employs 2,300 people around the world, said its export strategy has been supported by UK Export Finance as well as its banking partners HSBC and Lloyds Banking Group through Bank of Scotland.

Laurence Jamieson, relationship director at Bank of Scotland, said: "Alexander Dennis is an impressive Scottish success story and this latest announcement of the company further expanding its global footprint in Canada is testament to the strength of the Scottish manufacturing industry."

Earlier this week Alexander Dennis revealed it had won a 250-bus order from GKN in the UK.

That will see lower-emission vehicles deployed initially across London and Oxford before being rolled out more widely.

Those buses will also be fitted with the Gyrodrive system, which is based on technology from Formula One and designed to help use less fuel and improve efficiency.

Alexander Dennis saw its revenue grow from £481m to £541m in 2013, according to its annual accounts.

However a £21.9m provision made against the value of its Custom Coaches subsidiary, which was placed in administration in May this year, saw it make a pre-tax loss of £1.2m. That compared to a £24.2m profit for 2012.

The business is privately-owned with Sir Brian Souter and Ann Gloag's Highland Global Transport investment vehicle and Noble Grossart Investments listed among its shareholders on the company's most recent annual return.