Heathrow’s overseas backers have pledged £650 million in investments for major projects.

The consortium of investors would spend the money in 2019 on projects likely to include the expansion of Terminal 2 and a new southern access tunnel for road traffic to the airport.

The details of those projects will now be worked on by Heathrow and presented to the airport’s shareholders for approval.

The investment was discussed within the past week at the airport’s board meeting and suggests confidence by the overseas investors in the UK’s potential as negotiations with the EU get under way after the formal notification activating Article 50 yesterday.

Shareholders in the London hub, which handles more than 75 million passengers a year, include the Qatar Investment Authority, Singapore wealth fund GIC and the state-backed China Investment Corporation.

Heathrow said the investment would enhance the passenger experience at the airport and improve its ability to deal with the growing demand for its services.

It is already home to more than 80 airlines which serve more than 180 destinations.

The airport is understood to have around 30 airlines waiting to start services but which cannot be accommodated due to the lack of runway capacity.

Sheikh Abdullah Bin Mohammed Bin Saud Al-Thani, chief executive of Qatar Investment Authority, said: “Our investment in Heathrow is much more than just an investment in one of the world’s great airports – it’s an investment in Britain’s connections to the world.

“As the UK reshapes its role in the world, we confirm our commitment as proud partners of a great trading nation.”

Airport chief executive John Holland-Kaye described the investment as being “great news for Heathrow passengers and for Britain”.

A government draft national policy statement on the expansion of Heathrow with a third runway is being carried out with a vote in Parliament on the final document expected this winter.

A planning application is also being drafted by Heathrow alongside the Government’s policy statement and will be put before the planning inspectorate, which is expected to make a decision in 2020, meaning the new runway could be operational by 2025.