LONDON (AFP) - The head of London's British Museum will step down at the end of this year and is to work on a major new cultural project in Berlin, it said on Wednesday.

Art historian Neil MacGregor, who has been in charge since 2002, will leave in December to work on part-time projects including advising German Culture Minister Monika Gruetters on the development of the Humboldt Forum, a new museum due to open in 2019.

MacGregor "will go down as one of the greatest directors the 263-year-old British Museum has had", The Guardian said. Visitor numbers have increased from 4.6 million in 2002-3 to 6.7 million in 2014-5, making it the world's second-most visited museum after the Louvre in Paris.

One of MacGregor's most popular radio series was A History Of The World In 100 Objects in 2010. He organised a popular exhibition on German history last year at the British Museum.

The Humboldt Forum, a new museum due to open in 2019, is described by Gruetters as "our most ambitious cultural project" and will be housed in a former imperial palace in Berlin.

Media reports suggested that MacGregor could eventually be a candidate to run it.

After leaving the British Museum, he will also work alongside the CSMVS Museum in Mumbai - India's most prestigious - and on a new series for BBC radio.

During his time at the British Museum, he defended its right to keep its most controversial artefacts, the Elgin Marbles.

The museum's loan of part of the Elgin Marbles to the Hermitage Museum in St Petersburg last year drew an angry response from Greece, which wants the return of the sculptures which were once part of the Parthenon temple on the Acropolis in Athens.