Cellar Stairs, Door at the top, regs?

[compact]

We have extended the kitchen, by removing a meter square landing at the top of the cellar stairs.
We now want to put a door (bi-fold) opening into the kitchen, at the top of the stairs.
The question is are there any regs about having a space behind the door, i.e. a floor level top step of say 22cm?
We would like it so you open the door, there are a couple of inches of floor and then down to the top step.

I know this having a some room at the top as soon as you open the door would make life easier, but we would know about the step down issue.

The regs question also concerns that we will be renovating the cellar into a utility room with washer, weights etc.

Thanks

 

[jeds]

The landing at the top of the stair must be equal to the width of the stair. So a 600mm wide stair needs a 600mm landing before the door. Also, if the door opens towards the stair, the leading edge of the door must be minimum 400mm away from the top nosing when the door is fully open. (or is it 450mm? can't remember but it's one or t'other.) Having said that, in existing houses BC will often negotiate.