LONDON (AFP) - Two works by mystery British artist Banksy and belonging to singer Robbie Williams were sold for several million pounds at auction in London on Wednesday (March 2).

Vandalised Oil (Choppers), showing two low-flying military helicopters buzzing a pastoral idyll, went for nearly £4.4 million (S$8 million).

The work - described by auction house Sotheby's as depicting the artist's "anti-war message" - had been expected to go for between £2.5 million and £3.5 million.

The tableau recalls Apocalypse Now, the 1979 film about the Vietnam war, when American attack helicopters strafe enemy positions to German composer Richard Wagner's Ride Of The Valkyries.

In its catalogue note, Sotheby's said it also reflected Banksy's opposition to the second Iraq war when he handed out stencilled placards at London protests in 2003.

Another Banksy owned by Williams, Girl With Balloon, in spray paint on metal, sold for over £2.8 million, having been priced at £2 million to £3 million.

Williams, formerly of British boy band Take That, acquired it directly from the elusive graffiti artist in 2006.

The picture is one of Banksy's most famous images, showing a young girl holding her hand out towards a red heart-shaped balloon.

He has reproduced the image in a number of different forms.

A partially shredded version - Love Is In The Bin - sold at Sotheby's in October last year for a staggering £18.58 million in a new record for a British artist.

The artwork had been bought three years earlier for a fraction of the price, but soared in value when it was passed through a shredder hidden in its frame.

In March 2021, another Banksy work, Game Changer, honouring medical staff during the pandemic, sold for £14.4 million at Christie's.

The proceeds were donated to the state-run National Health Service.