It took place in St John’s Square and coincided with similar ceremonies in towns and cities across the country following on from the national proclamation event, taking place at St James's Palace, London, on Saturday.
Here’s the best of our pictures from photographer Iain Lynn.
1. Royal proclamation in St John's Square
Tributes and messages of condolence Photo: Iain Lynn
2. Royal proclamation in St John's Square
The ceremony took place at 3pm along with many across the county. Photo: Iain Lynn
3. Royal proclamation in St John's Square
Crowds in Blackpool watch the Mayor of Blackpool read the royal proclamation Photo: Iain Lynn
4. Royal proclamation in St John's Square
A marmalade sandwich - Paddington's favourite Photo: Iain Lynn
5. Royal proclamation in St John's Square
Crowds in Blackpool watch the Mayor of Blackpool read the royal proclamation in St John's Square Photo: Iain Lynn
6. Royal proclamation in St John's Square
The ceremony was one of many across the country to welcome King Charles III Photo: Iain Lynn