Anyone intending to install a mezzanine floor should look at all the works being carried out, and consider whether to deal with the mezzanine and the other works under separate planning applications.
Ordinarily you would expect installation of a mezzanine floor to incur a CIL liability (community infrastructure levy) given CIL is generally payable whenever floor area is increased by works carried out pursuant to a planning permission.
However, CIL is not payable where the requirement for planning permission only arises because of directions made under a particular section of the Town and Country Planning Act 1990 (s.55(2A)). Installation of mezzanine floors falls within that category. Generally planning permission is not required for internal works, and planning is only required for the installation of mezzanines because of a direction made under that section.
So if the only works being carried out are to install a mezzanine floor then CIL should not apply, given planning permission is generally not needed for internal only works. If any other works being carried out require planning permission regardless of s.55 (2A) then it would pay to apply for planning for those works separately. One shopping centre did just that and saved over £170,000 in CIL liability as a result. But act quickly – the courts have flagged this as a loophole Parliament should close.