On Thursday 15 April only, take a re-usable travel flask into Starbucks and get any sized free hot or iced espresso drink worth about £2.65. Any drink with an espresso shot is included in the offer, for example a latte, cappuccino, americano, macchiato, inc. flavoured versions.

The offer's available nationwide from 7am to 11pm (provided your local store is open) at participating stores. For full details read about Starbuck's eco campaign 'the Big Picture'.

What counts as a reusable travel mug? It needs to be something you can transport your coffee in easily and that you will use again, eg a polystyrene cup won't work. A ceramic mug from home won't be accepted either. A bog-standard packed lunch flask should do the trick!