In the 1950's there were thought to be 30 million hedgehogs in the UK; estimates today suggest there are less than one million.
The decline of hedgehogs in the UK is comparable to the loss of tigers globally
It is a shocking statistic for a mammal that has been here since the time of sabre-toothed tigers and woolly mammoths.
The British Hedgehog Preservation Society is highlighting the problems faced by the nation’s hedgehogs, and what can be done to help them, during its annual week-long event.
According to Fay Vass, the society’s chief executive: "The decline of hedgehogs in the UK is comparable to the loss of tigers globally."
Hedgehog Awareness Week runs from the 3rd to the 9th of May and this year the focus is on gardens, and the simple measures that can be taken to make a positive difference.
The main problem they face is loss and fragmentation of habitat.
“There are pockets of land that are good for hedgehogs, but they don't join up any more,” Fay tells BBC Earth.
It is important because hedgehogs will travel between one and two miles a night and need space to thrive.
So the British Hedgehog Preservation Society is asking people to open up their gardens to hedgehogs, recreating wildlife corridors. A CD case sized gap is perfect and will make a big difference.
"Offering hedgehog food or meaty pet food and water is good too, especially during dry weather," says Fay.
"And look out for hedgehogs in the garden, carefully check before strimming, mowing, burning or jabbing a fork in anything."
The British Hedgehog Preservation Society has lots of tips on how to help hedgehogs.
And with their partners at the People's Trust for Endangered Species they have launched a project called Hedgehog Street where people can cooperate and even map their holes in the fence.
Hedgehogs regularly top the polls of favourite and most iconic UK species.
Fay suggests that this is because they are very accessible, and a lot of people have one of their first wildlife experiences with hedgehogs.
“The hedgehog's instinct to curl up rather than run away gives us chance to wait quietly and be rewarded with the hedgehog slowly emerging and going about its business."
Fay goes on to say that these "simply adorable" mammals do no harm and are very useful pest controllers so are loved by gardeners too.
You can follow BBC Earth on Twitter, Facebook and Instagram.