Australian airline Qantas will place an order next year for planes capable of making the 20-hour flight between London and Sydney.

Chief executive Alan Joyce told the BBC he was in advanced discussions with planemakers Airbus and Boeing.

Flights could start around 2022 if they produced the right aircraft, he said.

Qantas also plans to fly non-stop from Australia to North America - slightly shorter than the London-Sydney non-stop flight.

Mr Joyce told the BBC's Today Programme he was confident there would be demand for the flight.

"Business traffic and general leisure customers would rather have the certainty of getting there direct, not having to stop, not having connections gone wrong, the extra speed that that entails is really important," he said.

In March, the airline launched non-stop flights between London and Perth, a flight lasting just over 17 hours.

Mr Joyce said since their launch the flights had on average been 92% full, with business class even higher at 94%.

He said, however, that there was no plane yet that could handle the longer London and Sydney flight.

Qantas is considering the Airbus A350-1000 for the flight but said the plane would need "modification" because it "needs a little bit more range to get there".

Boeing's 777-8, the new version of its 777 plane, which is expected to be ready in 2022. is also under consideration.

If the non-stop flights - dubbed Project Sunrise - go ahead, Mr Joyce said the airline would also start offering non-stop flights to New York as well.

"Qantas is unique because we can probably justify a large number of these long haul aircraft, given how far Australia is from the rest of the world," he said.

And Qantas is not the only airline targeting long non-stop flights.

Singapore Airlines will launch a non-stop flight in October from Singapore to Newark, New Jersey - a journey that will take nearly 19 hours.

Meanwhile, Qatar currently offers the longest non-stop flight available: its Auckland to Doha route which takes 17.5 hours.