Is it Fine to Tile Over This on Bathroom Wall?

[Chazza231]

Hi there,

I’m currently in the process of renewing my bathroom and need some advice on tiling! I’ve taken the old tiles and and have been left with this (see picture). Is it alright to tile straight on to this after I’ve removed all loose plaster/rawplugs etc and filled all holes, then primed the walls with Mapei Primer G? Or should I get it skimmed or backing boards??

I’m going to be using 600x600mm porcelain tiles with Kerflex Maxi S1 slow setting adhesive and keracolour FF 100 grout

Thanks in advance!