LONDON (AFP) - Only a quarter of Britons believe that the Elgin Marbles, the ancient sculptures that once decorated the Parthenon temple in Athens, should remain in London's British Museum, according to a poll published Tuesday.

Half of the respondents to the YouGov survey published in the Times said the artefacts, also known as the Parthenon Marbles, should be returned to Greece, with a quarter undecided.

For three decades, Greece has called for the return of the sculptures, which decorated the Acropolis of Athens for more than 2,000 years.

Elgin insisted he had permission to take the works from the Ottoman Empire, which ruled Greece at the time.

A slim majority in the YouGov survey backed the museum's controversial decision to loan the works, which were taken from the Parthenon by British diplomat Lord Elgin in 1803, to Russia's State Hermitage Museum.

Thirty-nine percent believed it was the right decision, against 37 who were opposed.

The sculpture of the Greek river god Ilissos, a headless, reclining male figure, will be displayed in Russia's second city of Saint Petersburg until January 18.

It is the first time one of the sculptures has left their British home and marks the British Museum's 250th anniversary.

The chairman of the museum's trustees, Richard Lambert, said it was the institution's "duty" to allow people "in as many countries as possible to share in their common inheritance".