Can I decline a Section 106? - Public forum - Planning Advisory Service (PAS)

The clue is in the name. It's an "agreement". However, if used properly, it is the thing that is required to make a development acceptable. So, no agreement = no permission.

Yes but then you might not get planning permission as a result!

If policies support the S106 then negotiate if you find it unacceptable, you must provide evidence which supprts your position, never sign an agreement if you are unhappy with the content because as sure as eggs is eggs you will regret it later. If planners are intransigent appeal against the imposition, but get your facts right first.