Why can't it be slugs or snails Guest? They are the obvious culprits

there are slug pellets all around and some empty snail shells so i thought i had sorted that one.

Probably the only way to find out is to creep out after dark on a damp night with a torch and investigate. It does sound like slugs and snails though. If the slug pellets aren't working or you want a more environentally friendly approach you can use a half grapefruit skin with an entry hole to trap them ( they like hiding in them) or I found they are very partial to guinea pig food in a rodent sized pet bowl, though you will need to remove them while they are in the bowl obviously. I found this out by accident when I kept a rabbit and guinea pig outside and regularly found a mass of slugs in their bowl on rainy nights that I would have to remove.

Thank you so much weedfingers - you're an angel! At my age (not telling) I am ashamed to say that I am new to growing veg - it was a book about growing them in pots that got me interested and I just wanted to prevent rather than kill pests. I will be out with my torch tonight and buying the guinea pig food tomorrow (the attraction there will be the molasses ... of course ... I knew that they love sweet things) then I can deposit the little horrors in the local wood and scoop up those murderous pellets. Why aren't they touching my lettuces though? - all my plants are in pots on the patio together so I would have thought they'd all be snaffled by beasties.

You are welcome Dizijan, I have got to that age as well, I know how it is!

I don't know much about veg either, I have made an adventurously sized pond in a very small garden and don't really have room to grow more veg than fits into a metre square plus a few pots which is not much room at all. I am trying though!

If you are slug and snail hunting they only really come out in force when it is nice and rainy or very humid and damp, although if you water the garden thoroughly then that will have the same effect of encouraging them to leave their hiding places when they can be hunted down.

The guinea pig food I used was called Burgess and was pellets rather than muesli , I felt sorry for the guinea pig and rabbit as there would be multiples of slimy pests inside inside the bowl and I would have to go nightly to remove a whole mass of them when it was rainy outside. The snails and slugs loved that food. I, used to take them away in a carton and release them in farmland. One night rather creepily someone started following me in a car . When I reported it to the police the officer was trying not to laugh when I mentioned I had been driving late in thick fog to drop some snails off. They obviously thought I was completely mad!

If you do get the food, it will be more attractive to the slugs if is is moistened a little.