Screwfix 85886
Price: £14.99 Length: 3.5 metre
RECOMMENDED Here’s a surprise. Despite being among the cheapest here, the leads are helpfully longer than the other budget-end offerings, and electrically they’re excellent. There was a volt drop of only 94 millivolts per metre, which is no doubt due to the 25mm copper cores. And according to Screwfix, they can start petrol engines up to 5.5 litres.