Presenter Laurence Knight heads to the Ineos oil refinery in Grangemouth, Scotland, to see how just a smidge of a titanium-based catalyst transforms a type of natural gas into the stuff of food packaging, bottles and car bumpers.

He hears from Prof Andrea Sella why most of us spend our lives surrounded by titanium without even realising it.

And Brian Pickett of pigments manufacturer Cristal explains why his company has been painting various bits of London to further the fight against city smog.

(Picture: Window cleaner; Credit: Peter Parks/Getty Images)