Cat food, a dish of water, kibbled peanuts, but no bread and milk: hedgehogs are lactose intolerant,

Numbers in the UK are going down as fast as tigers.
Why?
Incremental loss of habitat, slug pellets, declining numbers of bugs (remember when car windshields got covered in insects?), the vogue for decking and shingle, farmers removing hedges, pesticides, strimmer and mower injuries... they are vulnerable creatures. The average life-span is 18 months. When food supply is poor, they eat too high a proportion of slugs, snails, and worms. Those carry really nasty parasites including lungworm, fluke, and coccidiosis, which can kill small weak animals very fast.

There are many rescues and excellent information sites.

Help hedgehogs by linking gardens, Hedgies need to forage 2-4 km per night. A hole at the base of a garden fence the size of a CD is all that's needed to give access.