From a1e5b321f39fb5fde9d4512d8f7e4d89ead212a4 Mon Sep 17 00:00:00 2001
From: Ruth Comer <ruth.comer@metoffice.gov.uk>
Date: Fri, 14 May 2021 20:42:07 +0100
Subject: [PATCH 1/2] quickplot: locate colourbar with any supplied axes

---
 docs/src/whatsnew/latest.rst     |  3 +++
 lib/iris/quickplot.py            |  2 +-
 lib/iris/tests/test_quickplot.py | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
index 3caf386ef6..1d5d2873f9 100644
--- a/docs/src/whatsnew/latest.rst
+++ b/docs/src/whatsnew/latest.rst
@@ -65,6 +65,9 @@ This document explains the changes made to Iris for this release
 #. `@rcomer`_ modified :func:`~iris.plot.contourf` to skip the special handling for
    antialiasing when data values are too low for it to have an effect.  This caused
    unexpected artifacts in some edge cases, as shown at :issue:`4086`. (:pull:`4150`)
+   
+#. `@rcomer`_ modified :mod:`iris.quickplot` so that, if an axes is supplied, any
+   colourbar will appear below it, fixing :issue:`4126`.  (:pull:`4136`)
 
 
 💣 Incompatible Changes
diff --git a/lib/iris/quickplot.py b/lib/iris/quickplot.py
index 2eec514e9c..1b428693ec 100644
--- a/lib/iris/quickplot.py
+++ b/lib/iris/quickplot.py
@@ -72,7 +72,7 @@ def _label(cube, mode, result=None, ndims=2, coords=None, axes=None):
     if result is not None:
         draw_edges = mode == iris.coords.POINT_MODE
         bar = plt.colorbar(
-            result, orientation="horizontal", drawedges=draw_edges
+            result, orientation="horizontal", drawedges=draw_edges, ax=axes
         )
         has_known_units = not (
             cube.units.is_unknown() or cube.units.is_no_unit()
diff --git a/lib/iris/tests/test_quickplot.py b/lib/iris/tests/test_quickplot.py
index 8abbf48a94..405897ab20 100644
--- a/lib/iris/tests/test_quickplot.py
+++ b/lib/iris/tests/test_quickplot.py
@@ -247,5 +247,23 @@ def test_not_reference_time_units(self):
         self.check_graphic()
 
 
+@tests.skip_plot
+class TestColorbar(tests.IrisTest):
+    def test_colorbar_location(self):
+        theta = _load_theta()
+        theta_slice = next(
+            theta.slices(["model_level_number", "grid_longitude"])
+        )
+
+        fig1 = plt.figure()
+        plt.figure()
+        ax = fig1.add_subplot(1, 1, 1)
+
+        result = qplt.contourf(theta_slice, axes=ax)
+
+        # Colourbar should appear on same figure as ax, i.e. fig1.
+        self.assertIs(result.colorbar.ax.get_figure(), fig1)
+
+
 if __name__ == "__main__":
     tests.main()

From a7ef6971c5693fc9efc311739cfeaa52062d4005 Mon Sep 17 00:00:00 2001
From: Ruth Comer <ruth.comer@metoffice.gov.uk>
Date: Fri, 14 May 2021 20:53:05 +0100
Subject: [PATCH 2/2] add skip_data decorator

---
 lib/iris/tests/test_quickplot.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/iris/tests/test_quickplot.py b/lib/iris/tests/test_quickplot.py
index 405897ab20..0144b5c535 100644
--- a/lib/iris/tests/test_quickplot.py
+++ b/lib/iris/tests/test_quickplot.py
@@ -247,6 +247,7 @@ def test_not_reference_time_units(self):
         self.check_graphic()
 
 
+@tests.skip_data
 @tests.skip_plot
 class TestColorbar(tests.IrisTest):
     def test_colorbar_location(self):