Painting bare wood - to prime or not?

[pineapple]

The directions on the undercoat I had previously, said it could be used as a primer on bare wood as well as standard undercoat. But on the undercoat tins I have now, it says to use primer first.
The wood in question is some new skirting board in a bedroom. Could I get away with applying undercoat direct? What if I apply a thinned down coat first?
Cheers

 

[dcdec]

What you're describing sounds like the difference between acrylic primer undercoat and oil based undercoat.
The timber will need a primer if you apply an oil based uc or two coats of acrylic before top coat.
Don't forget the knotting solution.

 

[Robbie uk]

Couldnt have put it better myself !!