Follow Camera Interferes with Player Movement?

Hi This is the script attached to the main camera. Its a top down game and the camera is supposed to follow the player.

Instead, it stays where it is and doesn't let the player move around freely. Its like the player is attached to the centre of the screen on a bungie cord which isn't right. Player moves fine when the camera script is turned off.

 using System.Collections;
 
 public class CameraMovement : MonoBehaviour 
 {
     private Vector3 cameraTarget;
     private Transform target;
 
 
     void Start()
     {
         target = GameObject.FindGameObjectWithTag ("Player").transform;
     }
 
 
     void Update()
     {
         cameraTarget = new Vector3 (target.position.x, transform.position.y, target.position.z);
         transform.position = Vector3.Lerp (transform.position, cameraTarget, Time.deltaTime * 2);
 
     }
 }

Any ideas whats going wrong? I've this script work for others and similar scripts don't work either.

Harry