Changing to python2.7 interpreter in Spyder3

I have uninstalled Spyder2 and installed Spyder3. I was told that it would be easy to continue using the python2.7 interpreter in the new Spyder3. I changed the interpreter using Preferences > Console > Advanced settings > Use the following Python interpreter: changing this to /usr/bin/python2.7. It comes up with a warning:

You selected a Python 2 interpreter for the console but Spyder is running on Python 3!.

Although this is possible, we recommend you to install and run Spyder directly with your selected   interpreter, to avoid seeing false warnings and errors due to the incompatible syntax between these two Python versions.

I left the default PYTHONSTARTUP option.

Upon choosing to open a new python console I get the following which is correct:

Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 

Upon restarting the IPython console/kernel I get the following message:

An error ocurred while starting the kernel
Traceback (most recent call last):
File "/usr/lib/python3/dist‑packages/spyderlib/widgets/externalshell/start_ipython_kernel.py", line 186, in 
ipk_temp.config = kernel_config()
File "/usr/lib/python3/dist‑packages/spyderlib/widgets/externalshell/start_ipython_kernel.py", line 45, in kernel_config
from spyderlib.config import CONF
ImportError: No module named spyderlib.config

When I switch to the Python console and run my script I get the following message:

runfile('blablabla.../RT_param_compare.py',  wdir=r'blablabla...')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'runfile' is not defined

I am not sure what I should do to remedy this.

[jmokoistinen]

I found this one useful for anaconda:

Try typing these 3 lines from the anaconda command prompt: conda create -n spyder python=2.7 spyder conda activate spyder spyder

[jmokoistinen]

Yes sorry it should be source activate spyder

After activating Use conda or pip to install other libraries…