Damp patch on window reveal

[gizmo]

Donwstairs window has developed a damp patch from window frame moving in in a semi crcle shape. It gets a lot worse when it rains as you would expect, especially if it is also windy. We've re-sealed the outside window frame where it meets the wall and checked the window above and resealed that. It was a new window fitted about 12 months ago but it has only recently started leaking. Room has just been plastered but the fit of the old and new window was pretty good and it looked like a stratforward skimming job over the old plaster in the reveal. Can't work out what could be causing the water ingress at all. May be a stupid question but does anyone have any idea what could the problem could be? We're deperate now 'cos we have almost finsihed decorating the rest of the room. Would it be creating a problem if we tried sealing the surface where the damp patch is and painting over the top?

The water is obvioulsy getting into the cavity - it this causing a problem or is ot OK for rain to get into the cavity? HELP PLEASE!!!!!!!!!!

[paulboy]

i have exactly the same problem and am at my witts end as how to sort it out, ive resealed and done a bit of repointing but its not changed anything, ive not long repainted and have a tide mark which comes and goes when it dries out!, ii am not sure if the window has drain holes in them. my older windows suffer from this but my new ones dont. !!! need a solution to asap !!!