The Duke of Cambridge has paid tribute to the work of the Queen and the Duke of Edinburgh in protecting "vital outdoor places" as huge crowds came out for the latest leg of the Diamond Jubilee tour.
Thousands flocked to various parts of Nottingham to see the Queen, William and the Duchess of Cambridge as they continued the tour in the East Midlands.
The Duke of Edinburgh was originally scheduled to take part in the visit but had to cancel as he continues to recover from a bladder infection.
Visiting Vernon Park, William said: "I do feel something of an interloper here today. After all, the Queen has been patron of Fields In Trust for all 60 years of her reign. My grandfather, the Duke of Edinburgh, who very sadly cannot be here today, has been president for 64 years.
"This marvellous charity provides people of all ages up and down the country with the space to play sport, keep fit and generally get outside and enjoy themselves in the fresh air. Fields In Trust, I know, is very dear to my grandparents' hearts, as it is mine."
The Duke paid tribute to his grandparents and thanked them for protecting "vital outdoor places" such as Vernon Park for the nation and also the charity for its work.
Earlier, the royal party was greeted with cheers at the station concourse and were confronted by thousands more well-wishers as they moved to the city centre.
The Queen, who looked relaxed and smiled throughout the visit, talked to people in the square, some of whom arrived at 5am, before the royal party moved into the Council House. They appeared a few minutes later on the balcony of the building to a huge cheer while the national anthem was played.
The royal party then moved to the park, in the Basford area. The park is one of 1,300 recreational spaces to be given Queen Elizabeth II Fields Challenge status under the initiative to protect 2012 recreational spaces across the UK as a permanent legacy to mark the Jubilee.
Gyles Brandreth, vice president of Fields In Trust, declared: "This is an exciting day. This is a historic day for Nottingham."