The weekend's BAM was spent in my tent this time - a Terra Nova Laser that's now 8 or 9 years old.
Come the morning there was a fair amount of damp on the tent floor under the sleep mat - rest of the floor was dry, as was the inner shell. The outer had quite a bit of condensation inside. The base of the mat had picked up moisture as well but not the upper side. The vents at each end of the tent were open. Everything else inside the tent was dry.
My first thought was that the floor was weeping slightly with the pressure of my lying on it.
The other lads thought it could still be condensation. I'm familiar with interstitial condensation but I've not encountered this before.
So, do I need a footprint? Or more ventilation?

I had a small tent of a similar age and it started doing exactly that. I put it down to water seeping through the ground sheet due to the pressure from lying down.

Condensation below an insulated mat is pretty common.

Forget the tent and just use a bivvy bag Rich ... that way, you'll know it's condensation for certain

I wouldn't rule out condensation but the only way you'll likely know for sure, is to put something you know to be waterproof under the groundsheet.

Noticed my MSR Hubba Hubba has started doing this, I've put it down to it being old and the groundsheet not being as waterproof. Excuse to buy a new tent I think!

I made a footprint for my similarly aged Laser. It was def struggling on wet ground. Still impressed at how such a light tent has coped and lasted.

It was a very condensation prone night, my inner was very wet. Where I was set up it was dripping off the trees.

Just to be contrary , my tarp was reasonably dry in the same circumstances, certainly not dripping. Sleeping bag bone dry. Just a small damp patch on the Winterlite mat ( personal problem, best not go into it (*) ). Just follow The Way Of The Tarp .

(*) Nooooo! Joking.