The charity hopes that the census will help to identify where the nation’s stray cats are living.
A pilot scheme of the project launched in March in Nottingham, Everton, Bradford and Luton, and the organisation said it has received more than 2,000 reports of strays in these areas since.
Alongside this, the charity will be implementing a health check and neutering programme to control the number of strays on Britain’s streets and ensure they are looked after.
Also stray cats that are suitable for rehoming will be taken into care for adoption.
Cats Watch is a downloadable app, and the charity has asked users to take pictures of any stray cats they see and upload it to the platform. Since launching, over 20 groups and organisations have helped to identify strays in their area.
Stray cats can also be reported on the Cats Protection Facebook page, or by contacting representatives.
Cats Protection’s head of neutering, Jane Clements, said: “There has never been a project of this scale dedicated to finding out more and helping stray cats. We know that across the UK, there are scores of homeless cats – both in rural and urban locations – but information about them is limited. By tracking numbers and population densities, we can better target our neutering work in future to prevent numbers getting out of control.
“Although cats are very adaptable, life as a stray street cat is incredibly tough, and we want to do all we can to help improve their lives. Large numbers of unowned, unneutered cats can also be a nuisance to communities, so by carrying out this work we hope to improve the way cats and people live alongside each other.”