Male cats stand up and spray so it could still be cats. Foxes make the garden stink too.

Several things come to mind our smell came from a stray cat spraying around the front door during the night.
Or your elderly cat may have incontinence due to old age, a urinary infection or perhaps stressed a visit to the vet may help also there are sprays you can buy to neutralize the smell and a plug in that helps reduce the stress levels which can occur for all sorts of reasons.

Got any Box plants out there? Or Viburnum tinus? The latter, especially if its suffered an attack of viburnum beetle, will smell horrible like this. Link below might be of interest, its not exactly scientific (doesn't mention viburnum beetle) but does mention a few plants, although it fails to mention fig, in particular, dwarf fig, which is also frequently the culprit... brushing against the leaves might well mean you carry the scent on your clothing

http://www.ehow.co.uk/list_7481805_plants-smell-like-cat-urine.html

On the other hand, it could just be fox urine... and a personal observation, Gaultheria procumbens can smell horrible, specially this time of year - not sure its exactly cat pee, but not far off.

Choisya is another that members of our flower club complain smells of cat wee.

I think it depends on how a person perceives scent - I hate the smell of Choisya foliage, particularly when its crushed, but other people I know think its a lovely smell. I don't think it smells like cat's wee though, it just plain reeks...

Flowering current smells like that as well.

Thanks guys. I think here in rural Shropshire I just have to put up with smells of local wild life including the large amounts of cats in our neighbourhood as have ruled out any of the before mentioned plants. Sigh.....

I found the source of the horrible smell! It has been soaked up in the soles of my wellies! I must have stepped into an area and now no matter how I scrub my boots the smells follows me everywhere! Nice! We were driving home from a family walk and the smell of cat wee was nauseating and it came from my lovely wellies! Will have to get some new ones cause my family are already calling me the old smelly cat lady!!

Well done Sherlock! Shame about the wellies but you can now buy yourself a new trendy pair. How about the tiger skin patterned ones, seems rather apt. :)

Camomile- yes will be looking for a new pair, glad I finally found the source because it was driving me crazy! I scrubbed and scrubbed but to no avail!! Quite fancy some polka dot ones-watch this space!

Seems a bit odd you can't get rid of the smell though - could it be the materials the boots are made from?

I think the odour has penetrated the plastic and they just reek of cat wee. Thought a (my) cat might have deliberately weed on them but the smell is only on the foot soles. They were cheap but lined, comfy wellies from Decathlon.