Britain's Heathrow has raised about 1.6 billion pounds from global investors to boost financial resilience ahead of Brexit and lay the groundwork for a privately funded expansion of Europe's busiest airport.

"With the outcome of Brexit negotiations unknown, strong businesses like Heathrow must stand up to support Britain's economy. We will expand Heathrow to boost Britain's global trade for decades to come," Heathrow Chief Executive John Holland-Kaye said on Friday.

The airport said funds raised from investors most recently included a debut Australian dollar issue.

"This extends our liquidity horizon until the end of 2020 and ensures the airport has sufficient financial firepower to cope with a no-deal Brexit and still meet its obligations - including progressing our expansion plans," it said in a statement.

Heathrow, owned by Ferrovial, Qatar Investment Authority and China Investment Corporation among others, said it continues to monitor Brexit progress and emphasized the importance of Britain agreeing to a deal with the EU that "secures continued liberal access to the European aviation market."

Most of the services at Heathrow are either not affected by the UK's relationship with the EU or would be replicated by bilateral agreements either before or very quickly after Brexit, the company added.

A hearing will take place in March to consider legal challenges to the British government's planned expansion of the airport. Heathrow said it was on track to submit a planning application in 2020 and for flights from the new runway to start in 2026.

Heathrow also reported a 2.3 percent rise in revenue to 2.21 billion pounds (2.8 billion US dollars) for the nine months to September 30, helped by passenger numbers up to a record 60.5 million. Adjusted core earnings rose 1.9 percent to 1.37 billion pounds.