Queen welcomes President Barack Obama to Buckingham Palace

The Queen has welcomed Barack and Michelle Obama to Buckingham Palace at the start of their three-day visit to the UK.

The trip began with Barack Obama being formally greeted by the Prince of Wales and the Duchess of Cornwall at the US ambassador's residence, Winfield House.

The Obamas will stay at the palace for one night.

Emily Maitlis and Nicholas Witchell report.