The crowd was also played a video message from former England captain David Beckham.
After the Government committed to giving an extra £375 million to help feed the world's poorest children, Beckham said:
We've had good news. Earlier today the Prime Minister met with other world leaders and has made a real commitment to ending child malnutrition and hunger. There is more to do though and you can help.
More top news
Home Secretary Theresa May and French counterpart Bernard Cazeneuve call on EU nations to tackle the root causes of the migrant crisis.
Downing Street is likely to confirm that the UK will fund extra security guards at the Eurotunnel perimeter.
Very warm in the southeast tomorrow