Are ethical funds any good? The best ethical funds to invest in

I recently received a great question via Chatterbox which I answer in full in this article.  I've pasted the original question below for ease of reference:

Hi Damien,

I’m totally new to M2TM but really, really enjoying it so far. I thought I’d get involved and ask a question on the forum.

I’ve just read a piece on Good with Money about voting with your pound and putting your money where your morals are. And personally whilst I have noble intents in this area I do also want to balance it against the need to get a semi-decent return.

I don’t think there are any ethical funds which are in your Best of the Best. But I am wondering if you have ever done any research into which ethical ones are the best ones out there. I have a few ethical funds in my existing portfolio but want to make sure I am sticking the right ones in there that give decent returns, if any do.