The new code will extend across 14 destinations in Malaysia, including Langkawi, Penang and Kota Kinabalu, and a further nine cities in Australia, Cambodia, Indonesia, New Zealand and Vietnam.

Codesharing seats are available to book now for travel from 9 October.

The new arrangements will open up more routes, destinations, fares and flexibility for passengers travelling between the UK and the Asia-Pacific region.

Passengers will be able to collect their boarding passes in advance and check their luggage through to their final destination seamlessly.

BA Executive Club members will be able to access enhanced frequent flyer benefits from codesharing flights, while Avios can be used on reward flights, upgrades, hotels, experiences and for part payment.

BA currently operates direct daily flights between Heathrow and Kuala Lumpur, a hub for oneworld alliance members

Malaysia Airlines customers will be able to book BA seats on its website to Aberdeen, Belfast, Edinburgh, Glasgow, Manchester and Newcastle, via Heathrow.

Subject to regulatory approval, Malaysia Airlines will also codeshare with BA on other European routes, including Barcelona, Berlin, Copenhagen, Vienna, Brussels, Geneva, Hamburg, Lyon, Toulouse, Paris and Zurich.

Its full BA codeshare destinations are: Alor Setar, Kota Kinabalu, Johor Bahru, Kuching, Kuantan, Labuan, Langkawi, Miri, Penang, Sibu, Kuala Terengganu, Sandakan, Kota Bharu and Bintulu (Malaysia); Adelaide, Melbourne and Perth (Australia); Auckland (New Zealand); Denpasar-Bali, Jakarta and Surabaya (Indonesia); Ho Chi Minh City (Vietnam); and Phnom Penh (Cambodia).

Neil Chernoff, BA director of networks and alliances, said: “This codeshare with Malaysia Airlines further strengthens the destination proposition for our customers, giving them more benefits when flying to Asia and South West Pacific.”