diff --git a/lib/iris/_lazy_data.py b/lib/iris/_lazy_data.py
index e77fca0dd1..221dca5569 100644
--- a/lib/iris/_lazy_data.py
+++ b/lib/iris/_lazy_data.py
@@ -31,30 +31,6 @@
 import numpy.ma as ma
 
 
-def _iris_dask_defaults():
-    """
-    Set dask defaults for Iris. The current default dask operation mode for
-    Iris is running single-threaded using `dask.local.get_sync`. This default
-    ensures that running Iris under "normal" conditions will not use up all
-    available computational resource.
-
-    Otherwise, by default, `dask` will use a multi-threaded scheduler that uses
-    all available CPUs.
-
-    .. note::
-        We only want Iris to set dask options in the case where doing so will
-        not change user-specified options that have already been set.
-
-    """
-    if 'pool' not in dask.context._globals and \
-            'get' not in dask.context._globals:
-        dask.set_options(get=dget_sync)
-
-
-# Run this at import time to set dask options for Iris.
-_iris_dask_defaults()
-
-
 def is_lazy_data(data):
     """
     Return whether the argument is an Iris 'lazy' data array.
diff --git a/lib/iris/tests/unit/lazy_data/test_iris_dask_defaults.py b/lib/iris/tests/unit/lazy_data/test_iris_dask_defaults.py
deleted file mode 100644
index cc9bbdfa3e..0000000000
--- a/lib/iris/tests/unit/lazy_data/test_iris_dask_defaults.py
+++ /dev/null
@@ -1,63 +0,0 @@
-# (C) British Crown Copyright 2017, Met Office
-#
-# This file is part of Iris.
-#
-# Iris is free software: you can redistribute it and/or modify it under
-# the terms of the GNU Lesser General Public License as published by the
-# Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Iris is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU Lesser General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public License
-# along with Iris.  If not, see <http://www.gnu.org/licenses/>.
-"""
-Test :func:`iris._lazy data._iris_dask_defaults` function.
-
-"""
-
-from __future__ import (absolute_import, division, print_function)
-from six.moves import (filter, input, map, range, zip)  # noqa
-
-# Import iris.tests first so that some things can be initialised before
-# importing anything else.
-import iris.tests as tests
-
-from iris._lazy_data import _iris_dask_defaults
-
-
-class Test__iris_dask_defaults(tests.IrisTest):
-    def setUp(self):
-        set_options = 'dask.set_options'
-        self.patch_set_options = self.patch(set_options)
-        self.mock_get_sync = tests.mock.sentinel.get_sync
-        get_sync = 'iris._lazy_data.dget_sync'
-        self.patch_get_sync = self.patch(get_sync, self.mock_get_sync)
-
-    def test_no_user_options(self):
-        self.patch('dask.context._globals', {})
-        _iris_dask_defaults()
-        self.patch_set_options.assert_called_once_with(get=self.patch_get_sync)
-
-    def test_user_options__pool(self):
-        self.patch('dask.context._globals', {'pool': 5})
-        _iris_dask_defaults()
-        self.assertEqual(self.patch_set_options.call_count, 0)
-
-    def test_user_options__get(self):
-        self.patch('dask.context._globals', {'get': 'threaded'})
-        _iris_dask_defaults()
-        self.assertEqual(self.patch_set_options.call_count, 0)
-
-    def test_user_options__wibble(self):
-        # Test a user-specified dask option that does not affect Iris.
-        self.patch('dask.context._globals', {'wibble': 'foo'})
-        _iris_dask_defaults()
-        self.patch_set_options.assert_called_once_with(get=self.patch_get_sync)
-
-
-if __name__ == '__main__':
-    tests.main()