Let E be an elliptic curve defined over a number field K, let α ∈ E(K) be a point of infinite order, and let N −1 α be the set of N -division points of α in E(K). We prove strong effective and uniform results for the degrees of the Kummer extensions [K(E[N ], N −1 α) : K(E[N ])]. When K = Q, and under a minimal assumption on α, we show that the inequality [Q(E[N ], N −1 α) : Q(E[N ])] cN 2 holds with a constant c independent of both E and α.We shall often use divisibility conditions involving the symbols ℓ ∞ (where ℓ is a prime) and ∞. Our convention is that every power of ℓ divides ℓ ∞ , every positive integer divides ∞, and ℓ ∞ divides ∞.Recall from the Introduction that we denote by K M the field K(E[M ]) generated by the coordinates of the M -torsion points of E, and by K M,N (for N | M ) the field K(E[M ], N −1 α). We extend this notation by setting K ℓ ∞ = n K ℓ n , K ∞ = M K M , and more generally, forIf H is a subgroup of GL 2 (Z ℓ ), we denote by Z ℓ [H] the sub-Z ℓ -algebra of Mat 2 (Z ℓ ) generated by the elements of H.Let G be a (profinite) group. We write G ′ for its derived subgroup, namely, the subgroup of G (topologically) generated by commutators, and G ab = G/G ′ for its abelianisation, namely, its largest abelian (profinite) quotient. We say that a finite simple group S occurs in a profinite group G if there are closed subgroups H 1 , H 2 of G, with H 1 ⊳ H 2 , such that H 2 /H 1 is isomorphic to S. Finally, we denote by exp G the exponent of a finite group G, namely, the smallest integer e 1 such that g e = 1 for every g ∈ G.2.2. The ℓ-adic and adelic failures. We start by observing that it is enough to restrict our attention to the case N = M :Remark 2.1. Suppose that there is a constant C 1 satisfying M 2 [K M,M : K M ] divides C for all positive integers M . Then for any N | M , since [K M,M : K M,N ] divides (M/N ) 2 , we have that