The world remembers Mandela: Global leaders arrive in South Africa as 100,000 gather in Soweto for historic memorial service.

Barack and Michelle Obama travelled to South Africa on Air Force One with George W. Bush and Hillary Clinton

· Bill Clinton and Jimmy Carter are also attending today's memorial service but travelled to Africa separately

· David Cameron, Nick Clegg and three former Prime Ministers will be at the service in Johannesburg

· Mourners queued outside the 95,000-capacity FNB Stadium from early in the morning to secure a seat

· Ceremony started an hour late in pouring rain as leader said 'the gods are welcoming Mandela to heaven'

An unprecedented gathering of world leaders has come together in Johannesburg to pay tribute to Nelson Mandela at a memorial service for the former president of South Africa, five days after he died at the age of 95.

The ceremony at the FNB Stadium, the country's largest arena, started an hour late in the pouring rain after dignitaries and members of the public were filing in to the premises for hours.

Cyril Ramaphosa, the deputy president of the ruling ANC party who opened the proceedings, said: 'In our tradition, when it rains when you are buried, your gods are welcoming you to heaven.'

Barack Obama took a 17-hour flight from Washington on board Air Force One, during which he rode with his wife Michelle, former President George W. Bush, Laura Bush, and Hillary Clinton, but the American dignitaries were apparently late for the service.

He has been given a prominent role in the memorial service for the former South African president - but may face awkward moments if he comes face to face with controversial leaders such as Raul Castro of Cuba and Zimbabwe's Robert Mugabe.