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
Through the morning an area of rain will steadily track northeastwards across central England.
An outdoor nursery where children are only allowed to play with toys they have made themselves has been named Britain's Best Nursery.
The prime minister said changes will be made to the Gender Recognition Act in order to reflect updated attitudes towards being transgender.