Let G be a finite soluble group, and let h(G) be the Fitting length of G. If ϕ is a fixed-point-free automorphism of G, that is C G (ϕ) = {1}, we denote by W (ϕ) the composition length of ϕ. A long-standing conjecture is that h(G) ≤ W (ϕ), and it is known that this bound is always true if the order of G is coprime to the order of ϕ. In this paper we find some bounds to h(G) in function of W (ϕ) without assuming that (|G|, |ϕ|) = 1. In particular we prove the validity of the "universal" bound h(G) < 7W (ϕ) 2. This improves the exponential bound known earlier from a special case of a theorem of Dade. MSC: 20D20, 20D40, 20F14.