Suppose M is a closed irreducible orientable 3-manifold, K is a knot in M , P and Q are bridge surfaces for K and K is not removable with respect to Q. We show that either Q is equivalent to P or d.K; P / Ä 2 .Q K/. If K is not a 2-bridge knot, then the result holds even if K is removable with respect to Q. As a corollary we show that if a knot in S 3 has high distance with respect to some bridge sphere and low bridge number, then the knot has a unique minimal bridge position.57M25, 57M27, 57M50