These days you can insure your mobile phone against just about anything, but drop it in a salty puddle or the bilge water and you may find the insurance company is less than cooperative.

That’s why a huge market for waterproof mobile phone cases has sprung up, ranging from £18 to £80.

The premium options include flaps for fitting headphones and chargers, while the cheaper end of the scale features lockable pouches and reusable phone condoms.

These smartphone accessories are becoming particularly popular among boaters, so in our latest gear test video we set out to thoroughly test six of the best.

And, in true MBM style, we also attempt a bodge job to see if a Sainsbury’s sandwich bag can do the same job for a fraction of the price.

Technical writer Greg Goulding bravely volunteered his brand new iPhone 5S to be our guinea pig and undergo the three-second dunk test.

To see whether his phone survived a particularly grueling day on our Orkney Longliner test boat, watch the video above.