Here's a startling fact. A single female cat can become parent, grandparent, and great-grandparent to up to 20 thousand descendants in just five years. Yes, you read that right. Twenty thousand cats.
And that's why animal charities are becoming over-run and are calling for drastic solutions. Cat Chat - the Kent-based charity - wants more vets to offer neutering or spaying for free, or at least at low cost.
David Johns has been to one cat rescue centre to see the extent of the problem.
He spoke to cat rehomer Sharon Weller and Sir Roger Gale MP.