diff --git a/firedrake/cython/dmcommon.pyx b/firedrake/cython/dmcommon.pyx
index b3919bc883..ec7ab631af 100644
--- a/firedrake/cython/dmcommon.pyx
+++ b/firedrake/cython/dmcommon.pyx
@@ -3700,42 +3700,6 @@ def mark_points_with_function_array(PETSc.DM plex,
             CHKERR(DMLabelSetValue(<DMLabel>dmlabel.dmlabel, p, label_value))
 
 
-def to_petsc_local_numbering(PETSc.Vec vec, V):
-    """
-    Reorder a PETSc Vec corresponding to a Firedrake Function w.r.t.
-    the PETSc natural numbering.
-
-    :arg vec: the PETSc Vec to reorder; must be a global vector
-    :arg V: the FunctionSpace of the Function which the Vec comes from
-    :ret out: a copy of the Vec, ordered with the PETSc natural numbering
-    """
-    cdef int dim, idx, start, end, p, d, k
-    cdef PetscInt dof, off
-    cdef PETSc.Vec out
-    cdef PETSc.Section section
-    cdef np.ndarray varray, oarray
-
-    section = V.dm.getGlobalSection()
-    out = vec.duplicate()
-    varray = vec.array_r
-    oarray = out.array
-    dim = V.value_size
-    idx = 0
-    start, end = vec.getOwnershipRange()
-    for p in range(*section.getChart()):
-        CHKERR(PetscSectionGetDof(section.sec, p, &dof))
-        if dof > 0:
-            CHKERR(PetscSectionGetOffset(section.sec, p, &off))
-            assert off >= 0
-            off *= dim
-            for d in range(dof):
-                for k in range(dim):
-                    oarray[idx] = varray[off + dim * d + k - start]
-                    idx += 1
-    assert idx == (end - start)
-    return out
-
-
 def create_halo_exchange_sf(PETSc.DM dm):
     """Create the halo exchange sf.