How to prepare walls before painting after wallpaper

[Rob_Quads]

I have now finished the joyfull task of removing the lovely woodchip wallpaper from my new bedroom. The walls had 2 layers of the stuff with the top layer painted.
That has now all been removed but it looks like under that they had a blue painted room. As a result of the scrapping getting the paper off the wall some of this paint has been scraped off exposing the bare plaster.

I am going to be painting the walls so need to now get them nice and flush. Which of the following is suitable

a) Knock off any expose/flakey bits of paint and then just get some skim filler and run over the whole thing. Then lightly sand to make smooth
OR
b) Go round scrapping all the blue paint off the wall then smooth off with a really thin skim to fill in the scrap marks?

Below are a couple pics of the state of the walls, showing a close-up of where the paint has come off

 

[Zampa]

You have got your work cut out there matey!

You seem to know your options well enough...two choices make good around the edges of all the paint or take the paint over and skim it with filler.

Its all down to how well the paint is adhered really....

But let me bring something esle into the equation first....lining paper.

Ive done these types of wall many times and no amount of filling, re filling, touching up, re filling again get em up to scratch, you really do need to be looking at lining them with a decent 1200 grade paper before you even consider painting...the lining will even out the surface and create an even texture for you to paint on.

Now back to your surface...if you just fill the walls you may have a problem with the edges of the paint breaking away..or the moisture from the filler getting behind it and causing it to lift.

So...

First thing i would do is give the whole wall a coat of dulux stain block (thinned by about 25%) dont rub it down first..you will scratch the bare plaster to bits....washing is ok though.....this will bond the surface down nicely in order for you to put the filler over (id reccomend gyproc easifil)
the sealer will also show up more of the surface blemishes.

Also....the edges of the lining paper may blow where it goes over the poorly adhered paint if the surface isnt sealed

Then sand it down and apply the lining paper...you dont have to cross line it as its being painted.

As for scrapping all the paint off.......if it comes off easy then this would be a good option (although you should still seal fill and line)

If its well stuck to the plaster then id leave it alone, you could be making a lot of work for yourself.