Alkaline batteries, although more expensive than other types, are by far the best option. They will typically outlast their 'carbon' or 'zinc chloride' counterparts by up to 7 times.

They offer high capacity, long service life, high drain performance and superior endurance makes them the best back-up for all battery powered devices.

*** In a recent test carried out by the UK's Channel 5 tv programme, 'The Gadget Show', the GP Ultra Alkaline battery came first for performance and price, compared with 15 other leading brands. ***