LABOUR dithering over whether to back Heathrow expansion could scupper billions of pounds-worth of investment in the UK, the airport’s boss has warned.

Thomas Woldbye warned investors ‘cannot wait forever’ and could pull the plug on the £33billion plans if Prime Minister Andy Burnham doesn’t give his backing to a third runway by the New Year.

This is when they must reportedly decide whether to submit a formal planning application for the new runway.

While expansion of the UK’s biggest airport was backed by former premier Sir Keir Starmer’s government as part of a wider attempt to boost growth in Britain’s sluggish economy, Mr Burnham is understood to have told transport secretary Heidi Alexander he’s ‘unconvinced’ by the need for a third runway at Heathrow.

But Mr Woldbye warned that the huge investment plan could be scuppered if it isn’t backed within weeks, dealing a blow to the government’s growth plans.

He said: ‘Our shareholders would like to do this.

‘They do think that things are taking a long time, and so far they have decided to be OK with that…But of course we cannot wait forever.’

Mr Burnham is understood to have told transport secretary Heidi Alexander he’s ‘unconvinced’ by the need for a third runway at Heathrow 

Heathrow boss Thomas Woldbye warned investors ‘cannot wait forever’ and could pull the plug on the £33billion expansion plans if Andy Burnham doesn’t give his backing to a third runway by the New Year 

The third runway expansion plans would see Heathrow’s capacity increase to 756,000 flights and 150 million passengers per year 

He added: ‘At some point in time we need a level of certainty.

‘I think by the end of the year we’ll be looking and saying: “Let’s assess this, let’s take stock and see where we are.”’

While passenger figures are down at the airport – 4 per cent lower year-on-year in September among UK fliers – Mr Woldbye said demand continues to outstrip capacity at the hub.

Expansion backers also point out that Heathrow is the UK’s biggest port by goods value and handled nearly £300billion-worth of goods last year – more than a quarter of UK trade by value.

Mr Woldbye, speaking to the Financial Times, added: ‘The debate about whether the UK needs additional hub airport capacity has been settled.

‘Businesses, trade unions, regional airports, airlines and politicians agree that better global connections are critical if the UK is to compete, trade and grow.’

‘This is not simply an investment in an airport.

‘It is an investment in the UK’s future competitiveness. At a time when other international hubs continue to grow and attract new routes, this country has an opportunity to strengthen its global connections and unlock growth in every nation and region.’

Mr Burnham, who voiced scepticism about expansion at the UK’s busiest airport while mayor of Greater Manchester, has refused to confirm his support since moving into No10.

He is understood to have met Ms Alexander in recent days to discuss the government’s position and told her he’s not convinced a third runway needs to be built, given recent approval of expansions at Gatwick, Luton, Stansted and London City airports.

In addition, sources said he cited a recent £2billion investment at Birmingham airport, which will more than double annual passenger numbers to 30 million a year.

The PM is also understood to be concerned that Heathrow expansion could concentrate growth too heavily in the south of England at the expense of other regions.

Labour’s initial support for a third runway was set out by former chancellor Rachel Reeves in January 2025.

Estimated to cost £33billion, including £1.5billion to move the M25 to build the runway, the scheme is expected to be fully privately financed.

The Qatar Investment Authority, Saudi Arabia’s Public Investment Fund and China Investment Corp are among those poised to bankroll the expansion plans.

It would see Heathrow’s capacity increase to 756,000 flights and 150 million passengers per year.

Ms Reeves previously suggested the runway could be open in 2035 but airport bosses have told ministers that timetable appears impossible to meet.

The airport aims to get planning permission by 2029, and from that point believes building the new runway within a decade to be a reasonable goal.