Most ‘family photo’ opportunities at important political events are hated by world leaders – at least that’s what the Press Association’s political photographer Stefan Rousseau reckons.

So instead of awkward formalities, the moment the-then Italian President Silvio Berlusconi grabbed the-then Russian President (now Prime Minister) Dmitry Medvedev and US president Barack Obama and posed casually at the G20 summit in London in 2009 was a great photo opportunity.

Alongside up to 70 other photographers Rousseau assumed others would have got the same great photo – but as he sent his snap out realised he was the only one who captured the embrace straight on.

In the video above, the photographer tells the tale of the classic shot, which was even used on The White House website.

In ‘The story behind the photo’ video series, available exclusively on BT.com, photographers offer insight on some of the Press Association’s best-known images.

Discover more stories behind the photos.