diff --git a/pytket/phir/routing.py b/pytket/phir/routing.py
deleted file mode 100644
index eaabb46..0000000
--- a/pytket/phir/routing.py
+++ /dev/null
@@ -1,34 +0,0 @@
-# Copyright (c) 2023 Quantinuum LLC.
-# INSERT LICENSE HERE
-"""
-Routing functions. For simulation we don't need to create a sequence of
-transport operations; we are only interested in the time cost to transport from
-one state to another.
-"""
-
-from __future__ import annotations
-
-
-def inverse(lst: list[int]) -> list[int]:
-    """Inverse of a permutation list. If a[i] = x, then inverse(a)[x] = i."""
-    inv = [-1] * len(lst)
-    for (i, elem) in enumerate(lst):
-        if not 0 <= elem < len(lst):
-            raise ValueError(f"List contains element not in range: {elem}")
-        if inv[elem] != -1:
-            raise ValueError(f"List contains duplicate elements: {lst}")
-        inv[elem] = i
-    return inv
-
-def transport_cost(init: list[int], goal: list[int], swap_cost: float) -> float:
-    """Cost of transport from init to goal.
-
-    This is based on the number of parallel swaps performed by Odd-Even
-    Transposition Sort, which is the maximum distance that any qubit travels.
-    """
-    if len(init) != len(goal):
-        raise ValueError(
-            f"init and goal lists have different lengths: {len(init)} vs. {len(goal)}"
-        )
-    n_swaps = max(abs(g - i) for (i, g) in zip(inverse(init), inverse(goal)))
-    return n_swaps * swap_cost