diff --git a/src/runner_doiact.h b/src/runner_doiact.h
index b91a949e0e0910f61bc0b8d5fd8a283dcb24835d..9a530ca2e983749d5cd6eea1c2b5822ce3c3305d 100644
--- a/src/runner_doiact.h
+++ b/src/runner_doiact.h
@@ -3189,47 +3189,3 @@ void DOSUB_SUBSET(struct runner *r, struct cell *ci, struct part *parts,
 
   if (gettimer) TIMER_TOC(TIMER_DOSUB_PAIR);
 }
-
-/**
- * @brief Determine which version of DOPAIR1 needs to be called depending on MPI, vectorisation and orientation of the cells or whether DOPAIR1 needs to be called at all.
- *
- * @param r #runner
- * @param ci #cell ci
- * @param cj #cell cj
- *
- */
-void DOPAIR1_BRANCH(struct runner *r, struct cell *ci, struct cell *cj) {
-
-  const struct engine *restrict e = r->e;
-
-#ifdef WITH_MPI
-  if (ci->nodeID != cj->nodeID) {
-    DOPAIR1_NOSORT(r, ci, cj);
-    return;
-  }
-#endif
-
-  /* Anything to do here? */
-  if (!cell_is_active(ci, e) && !cell_is_active(cj, e)) return;
-
-  /* Drift cells that are not drifted. */
-  if (!cell_is_drifted(ci, e)) cell_drift_particles(ci, e);
-  if (!cell_is_drifted(cj, e)) cell_drift_particles(cj, e);
-
-  /* Get the sort ID. */
-  double shift[3] = {0.0, 0.0, 0.0};
-  const int sid = space_getsid(e->s, &ci, &cj, shift);
-
-  /* Have the cells been sorted? */
-  if (!(ci->sorted & (1 << sid)) || !(cj->sorted & (1 << sid)))
-    error("Trying to interact unsorted cells.");
-
-#if defined(WITH_VECTORIZATION) && defined(GADGET2_SPH) && (DOPAIR1_BRANCH == runner_dopair1_density_branch)
- if(!sort_is_corner(sid))
-   runner_dopair1_density_vec(r, ci, cj);
- else
-  DOPAIR1(r, ci, cj);
-#else 
- DOPAIR1(r, ci, cj);
-#endif
-}