Burrowed hole in garden

[Iamcazzy]

I have a line of breezeblocks laid flat in front of my greenhouse door that acts as a small footpath. On RH side of the path is the house wall. On the LH side is a small strip of soil and then the concrete foundations of the greenhouse. The house wall goes down to about a metre below the surface whereas the green house foundation is about 50cm deep.The greenhouse sits on a rectangle of breezeblocks one block high.
Something has burrowed down in the narrow strip of soil in the last few days; there is a "hole" about 8cm long by 4cm wide and about 30cm deep. Now I laid the breezeblock path myself on compacted soil, so i know it's not subsidence of any sort.
What creature could burrow down in this manner? The odd mole or two are seen in the neighbourhood but could it be anything else?

Thanks

[rowanwitch]

rats can burrow..but a mole sounds more likely

[Frank97]

We have rats around here that burrow like that, they have burrowed under the concrete slab that the garage sits on and the patio. I live in the country btw surrounded by ditches so there is little that can be done about it.

[sallybb]

We have lots of voles, that make holes along the raised borders, Also lots of moles, The moles are a giveaway with the piles of soil and usual loose soil runs under the lawn. Dont you just love them!

[RATTER15]

Rats.

[Iamcazzy]

Thanks all. I was afraid it might be a rat!

[wildwood]

It obviously hasn't reached under the foundation yet so instead of filling the hole with soil, I would fill it with very small shingle so the same hole can't be re-dug.

[Iamcazzy]

Thanks Wildwood. That sounds good to me - I'll take your advice.