London Heathrow moved 5 percent more cargo in September than in the same month last year, keeping the UK's largest port by value on a growth trajectory while Westminster weighs whether to approve a third runway that would lift export capacity by up to 50 percent.

The year-on-year increase covers the airport's cargo operations across its route network. Volumes rose on lanes to and from the EU, North America and APAC. The sharpest decline came on Middle East flows, the airport's traffic figures show, marking the one soft spot in an otherwise positive month for Europe's premier hub.

The figures land in the middle of a decisive period for Heathrow's expansion case. The proposed third runway would raise cargo capacity by as much as half, a jump the airport argues would translate directly into export opportunities for British shippers.

What does the expansion mean for shippers and carriers?

Heathrow CEO Thomas Woldbye framed the stakes in uncompromising terms. "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," he said.

Woldbye put hard numbers on the project's projected footprint.

• More than 100,000 jobs unlocked
• £33 billion of private investment injected
• Export capacity increased for companies across the country
• New airlines, new destinations and greater consumer choice

For freight forwarders and cargo airlines, a 50 percent capacity increase at a hub that already handles the country's highest-value trade flows would open bellyhold and potentially freighter access that is currently constrained by slot availability. For exporters — particularly in high-value sectors that move by air — the airport's argument is that added hub capacity converts directly into market access.

The political backdrop has shifted in the airport's favour. UK Transport Secretary Heidi Alexander recently confirmed that Heathrow expansion is compatible with the country's net zero commitments by 2050, lending government weight to the proposal at a stage when climate objections have historically stalled the project.

Is the runway finally moving toward approval?

Woldbye argues the remaining obstacle is parliamentary will, not feasibility. "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," he said.

His closing argument leaned on readiness and momentum. "There is now a clear path forward. The private investment is available, the benefits are well understood and the Government has confirmed expansion can be delivered within net zero targets. After decades of discussion, Parliament now has the opportunity to unlock a project that can deliver lasting benefits for generations to come. We are ready to deliver it."

The competitive framing matters for carriers deciding where to place capacity. Rival European and Gulf hubs have expanded runway capacity while Heathrow has operated two runways, and Woldbye's warning that other hubs "continue to grow and attract new routes" points to the long-term risk of route and transfer cargo migrating away from the UK if expansion stalls again.

September's 5 percent cargo growth demonstrates demand is already there. Regional splits, however, suggest the recovery is uneven: the Middle East lane contracted while the EU, North America and APAC grew, a pattern that will shape how carriers allocate bellyhold capacity across Heathrow's network this winter.

With the Transport Secretary's net zero endorsement on record and the airport claiming private funding is in place, the decision now rests with Parliament. A green light would set in motion a capacity increase of up to 50 percent on UK export flows; further delay would leave the country's largest port by value growing demand against a fixed two-runway ceiling.