Controlling HS2 costs and delivering the project quickly are vital for its success, according to the new chairman of the £50bn high-speed rail scheme.

Not going ahead with HS2 would be “disastrous for the whole nation” said HS2 Ltd chairman Sir David Higgins yesterday.

Acknowledging the opposition that exists for the project, Sir David said that major new schemes were always challenging as they produced change.

Speaking at Old Oak Common rail depot in north-west London, Sir David, who has been Network Rail chief executive, said it was vital that the UK had a railway fit for the 21st century.

The new high-speed line – which would go through areas of Oxfordshire north-east of Bicester – would deliver the extra capacity vitally needed on a network suffering from “ageing infrastructure”, he said.

Formerly Olympic Delivery Association chief who oversaw the successful 2012 London Games, Australian Sir David appeared undaunted by his new role promoting a line whose first London to Birmingham phase runs through Tory heartlands in the Chilterns and is bitterly opposed by some councils and many residents.

Sir David said: “It’s a great job and HS2 is crucially important for the nation. Not to go ahead with HS2 would be disastrous for the whole country.

“We have to tell people that it’s going to be delivered quickly and that costs are going to be controlled.

“There was opposition to the Olympics. Major projects are always challenging because they bring change.”

Work on the first phase of HS2 is due to start in 2017 with completion due in 2026. A second phase, taking the line to north-west and north-east England in a Y-shaped route, is expected to be finished by 2032/33.

Sir David said: “We want to bring benefits earlier if possible, especially to the North.

“We don’t want to wait until 2033. This scheme will not only help London, but will also make the north of the country more economically sustainable.”

Plans for a new college to train the next generation of top engineers to work on the construction of HS2 were also announced yesterday.

The scheme will offer the necessary technical training, including rail engineering, environmental skills and construction to make HS2 a success and ensure it can be built by skilled British workers.

It will be the first new incorporated Further Education College in more than 20 years.

It is expected that HS2 will create up to 2,000 apprentices during the lifetime of construction. It is thought the college will open in 2017.

The cost of the entire project is currently £42.6bn, with a further £7.5bn for the high-speed trains.