In a few days I may have a rare chance to get messy with Mrs Piechap. However, both time and preparation facilities will be in short supply.

Can I therefore ask for your recommendations for quick-to-make (edible) pie recipes with readily available UK ingredients. I won't have the chance to whisk anything, heat anything up etc - the less prep involved the better.

My current plan is a layer of custard topped with squirty cream, but if you've got a better suggestion please let me know!

Don't use squirty cream. It melts in about eight seconds, gets in your eyes and stays there, and after a million baths you will still smell like rotting livestock.

I am desperate for a UK source or equivalent to Cool Whip. It *must* exist!

Yes, it absolutely wouldn't be my first choice but I'm struggling to think of anything else that's instant and prep-free.

We all pray for the day when Cool Whip comes to these shores!

Sainsbury's Cake batter (mixed with about half the water, no oil/eggs) and put into a flan base made using cake batter (made properly) baked in a flan tin... it's a nice thick gloopy pie that sticks and provides great coverage.

If you're looking for a UK Cool Whip equivalent then Dream Topping (old fashioned powdered type mixed with milk, maybe a little less milk than on the instructions) is about as close as you'll get.... Fold through some marshmallow fluff for extra thick and stickyness.

Both of those are easy to colour with food colouring should you want a colour other than white.

Sounds like your going to have a great time Piechap.
I must admit I still adore shaving foam pies.
Easy to make and easy to clean

Thanks for all the suggestions on this. In the end we abandoned the idea of the pies and just had fun with a few cartons of custard. No prep required and a good time was had by all!