I think I've got a r..a..t in my composter

[petunia]

Our composter is one of those lift-up ones with no bottom bit to it, and I think "an animal" has made a tunnel by the side of our shed (huge pile of earth spotted there between fence and shed) under the corner of the shed to underneath the composter.
DH and I were thinking of gingerly lifting up the composter and seeing if anything scampers out and (hopefully!) runs away, leave the composter empty for a while and hoping Ratty stays away.
Would this work, or should I just go straight to Environmental Health?

Could be a hedgehog, or a squirrel?

I was thinking that. I'm hoping it might be another animal, anything other than a rat. I think that's why I'd rather investigate first before getting E.H in.

Put wire mesh underneath, I spent an hour or so doing this yesterday. Level the ground out first, lay down plenty of mesh, and replace bin and contents.
Rats are much smaller than you so just open the top and shout a bit before you stop to persaude them to clear off.

before you start, even, not "stop".

if you compost kitchen scraps then it may well be a very happy rat, and soon it will be a happy rat family. scaring it away is only temporary - it will be back the minute your back is turned. You can generally tell if you have rats by looking inside the composter - the compost is all churned up, and it smells, and yes, that is the smell of rat poo and wee. urgh. lljkk's mesh is a great suggestion, just make sure it is really stout mesh with small spaces (the hard flat kind with square holes no more than an inch across) and pin it down and pin the composter over it if you can. Rats are nasty, disease-carrying things and you really have to deal with them. you can buy poison at B&Q, but the most important thing is to make sure they don't want to live in your bin. No cooked food, mesh over the bottom, and mess it up inside regularly.

Thanks for everyone's help. We (well, DH actually!) lifted off the composter, and saw something small and brownish run along the side of the shed. He thinks it was probably a mouse- plus having just read your post mta, about the smell makes us think it was a mouse even more because the compost didn't smell at all. Whatever it was had been most productive and made some good tunnels in all the compost!
Anyway, the composter is now empty (any stuff not composted is in an old dustbin) and the stuff that was composted is now spread on the garden (job needed doing anyway!) I shall make a journey to find some mesh in the next few days.
Thanks once again.

my next door neighbour gets rid of the rats in her compost bin by regularly jumping up and down on the heap - she says she has found a fair few flat rats at the bottom .

tbh, if the rats want to get to the compost bin they will chew through almost anything inc all but the strongest, most expensive wire IME but it sounds like you have mice.

Eggs shells on the compost bin are apparently a 'rat magnet'

flat rats...

I just knew I shouldn't have clicked on this thread. Will go and find a nice cosy recipe thread or similar...