One evening last week, Catherine Usiskin set off as usual to take her two dogs out for a night-time walk on Primrose Hill, a park in north London she has lived beside for 40 years. But she found the park closed. Instead, she had to walk around its perimeter. “We weren’t told, there were no notices, all of a sudden I’m locked out of the park with no idea,” says the 70-year-old