Plasterboard gap

[Barnboy]

I've tried searching about but can't find an answer to my question.

Do I leave any gap between the ceiling and wall plasterboard for skimming ? 

From all I can find the wall and ceiling boarding should be lightly butted with no significan gap, but I can't find an answer to the corner joint between the ceiling and walls, or even the internal wall corners.

Can someone in the know, let me know please ?

[nod]

No 

Board it as tight as you can 

[Barnboy]

Thank you,

My dad is old school and wanting me to leave a plasterboard nail sized gap, I'll make sure it's all tight.