Listener Raffi is tired of his morning coffee going cold by the time he's ready to drink it. There are plenty of products out there promising to do a better job than Raffi's flask, and they come with a range of price tags. But how do they work and what is the ideal drinking temperature? Dr Michael de Podesta, a chartered physicist and measurements expert, has been looking into these very questions. He joins Greg and Raffi in the studio to run through his experiments - and explain how 'double walled technology' works and whether it's the answer to Raffi's prayers. Michael's even been trying out a high tech cup that claims to instantly cool your drink to a perfect drinking temperature - and keep it there for hours. Insulated cups also claim to be leak proof, durable and - in some cases - dishwasher proof. So joining them for this one is Kamisha Darroux, principal scientific adviser for Which? to talk about the tests they do and which other features are worth spending your money on. So are insulated coffee cups the best thing since sliced bread?

PRESENTER: GREG FOOT