Paint advice

[Wingedharpy]

Quick question to the wise ones:
Can I use white undercoat paint in place of white emulsion?
I've filled a couple of small cracks and just need to paint over filler but have no emulsion.
Many thanks.

colour will not match, especially with age and dirt.

White emulsion is the cheapest paint you can get.

Buy it in a plastic tub (which re-seals easily), stir very well, decant a bit into a plastic pot.

Apply at least two mist coats, because filler is very absorbent