If you do not fight relocation you effectively relinquish any right to be regarded as a resident parent. If you do nothing, you will be in a very weak position should you later try to apply for contact, and shared residence will never be a possibility.
One in four separated mothers will relocate within 4 years, and it is sadly the case that relocation is associated with poorer outcomes for children even within intact families. In separated families relocation beyond a one hour drive is associated with very substantially reduced outcomes. There is no evidential justification for the common judicial opinion that allowing the resident parent to relocate with the child is in the child’s best interests.
It is very difficult to prevent internal relocation, though the Court may, under Section 11(7) of the Children Act, impose conditions on any order already made under Section 8. These conditions can include restricting a parent to a geographical location.
One option, used in in Re E (Residence: Imposition of Conditions)  2 FLR 638 and Re T (A Child)  EWCA Civ 20is for the Court to impose a condition under Section 11(7) of the Children Act; this is a matter for the discretion of the judge and only to be used in exceptional circumstances. The only situation in which such an application is likely to be allowed is where there is already an established history of obstructed contact in which the intention to move is only the most recent tactic.
The courts now tend to frown on the imposition of conditions, however, and the preferred option, as expressed in Re F (Shared Residence Order)  EWCA Civ 592, is to apply for a Prohibited Steps Order.
The same principle of ‘detrimental impact’ which applies in leave to remove cases also applies in internal relocation cases; this is discussed below and the case to refer to is Re W (Children)  EWCA Civ 160.
The appropriate decision, in cases where the Court has concerns about the ability of the resident parent to be a ‘satisfactory carer’ would be to transfer residence, but in the absence of such concerns no conditions should be imposed.
Your best option very often will be to move as well, though this can then lead to an unseemly and expensive chase around the country.
 Data from the US in Ford, C. Untying the relocation knot: recent developments and a model for change. Journal of Gender and Law, 1997
 Humke, C. and C. Schaeffer, Relocation: A review of the effects of residential mobility on children and adolescents. Psychology: A Journal of Human Behavior, 1995
 Braver, S.L., I.M. Ellman, and W. Fabricius, Relocation of children after divorce and children’s best interests: New evidence and legal considerations. Journal of Family Psychology, 2003