d = iris.load_cube('./some_cube.nc')
os.chdir('some_other_dir')
d.data

---------------------------------------------------------------------------
IOError                                   Traceback (most recent call last)
<ipython-input-9-1780462823f7> in <module>()
----> 1 d[0][0,0,0,0].data

/home/niall/anaconda/lib/python2.7/site-packages/iris/cube.pyc in data(self)
   1448         if not isinstance(data, np.ndarray):
   1449             try:
-> 1450                 data = data.masked_array()
   1451             except MemoryError:
   1452                 msg = "Failed to create the cube's data as there was not" \

/home/niall/anaconda/lib/python2.7/site-packages/biggus/__init__.pyc in masked_array(self)
    814 
    815     def masked_array(self):
--> 816         array = self._apply_keys()
    817         # We want the shape of the result to match the shape of the
    818         # Array, so where we've ended up with an array-scalar,

/home/niall/anaconda/lib/python2.7/site-packages/biggus/__init__.pyc in _apply_keys(self)
    872                 array = np.take(array, key, axis=dimensions[i])
    873         else:
--> 874             array = self.concrete.__getitem__(keys)
    875         return array
    876 

/home/niall/anaconda/lib/python2.7/site-packages/iris/fileformats/pp.pyc in __getitem__(self, keys)
    662 
    663     def __getitem__(self, keys):
--> 664         with open(self.path, 'rb') as pp_file:
    665             pp_file.seek(self.offset, os.SEEK_SET)
    666             data_bytes = pp_file.read(self.data_len)