diff --git a/gusto/equations.py b/gusto/equations.py
index c1ec44641..a8f9e000b 100644
--- a/gusto/equations.py
+++ b/gusto/equations.py
@@ -1325,7 +1325,7 @@ def __init__(self, domain, parameters,
 
         w, phi, gamma = self.tests[0:3]
         u, p, b = split(self.X)
-        u_trial = split(self.trials)[0]
+        u_trial, p_trial, _ = split(self.trials)
         _, p_bar, b_bar = split(self.X_ref)
 
         # -------------------------------------------------------------------- #