It's not easy winning a PR fight when you're up against three octogenarian nuns whose story has become a global smash.

This week, David Yelland and Simon Lewis look at the case of Sister Bernadette, Sister Regina and Sister Rita. They ran away from the care home they'd been sent to and broke back into the Austrian convent where they'd lived for more than 60 years. In the process, they've gained huge support on social media.

Now, they've been told they can stay at the convent - so long as they stop posting online. The nuns and their hundreds of thousands of followers aren't happy.

David and Simon explain why harnessing authentic, joyful, grassroots support is the PR holy grail - and why it's almost impossible to counter. It almost doesn't matter what the Church authorities say or do. The facts are no longer important if people have already decided who is in the right and wrong.

On the extended edition on BBC Sounds, there's the distinct whiff of crisis at Campbell's. Its CEO has had to go on the record to insist the chicken used in its soups is "not made with a 3D printer". This follows a secret recording of a senior member of staff, who seemingly said the opposite during a long rant about the company.

The claim is clearly nonsense so David and Simon look at whether Campbell's reaction is proportionate - or whether we now live in a world where a company has to respond, no matter how ludicrous a claim seems.

Keeping your customers happy is of course vital in any business. Which brings us to Turkish Airlines. It's facing accusations of poor treatment after the former BBC correspondent, Mark Mardell, was told he wasn't allowed to board a flight because of his Parkinson's. David and Simon examine the response - or lack of - from Turkish Airlines and explain why getting ahead of a PR problem is absolutely crucial.

Producer: Duncan Middleton