Engine Mechanical problem
1996 Other Peugeot Models 6 cyl Front Wheel Drive Manual

hi i have a peugeot 306 two days ago and again today when there was quite bad ice on the car the car refused to start all of the warning lights etc came on but the car wouldnt even turn over. I naturally tried the battery jump starting and using a battery charger/starter did nothing. on using a battery tester showed the battery was fully charged. Yesterday when the weather was not as cold the car started perfectly. Could you please kindly tell me what it could be. Many thanks