How to survive
The safest plan may seem bizarre: risking it back in the UK with the ice. It would be possible to store lots of canned and dried food -- perhaps enough to live off indefinitely. However, attacks from fellow survivors, vicious, feral dogs and even zoo animals would be likely.
Of course you could eat any mammal that came your way; deer and squirrel might be clinging onto survival if they could find food. You would also need to source vitamins from somewhere. In the winter months when no food is available, First Nation and Swedish peoples obtain vitamin C from boiling up pine needles to brew a drink known as "tallstrunt". Although, neither will stave off the cold as the body uses up almost half of its calorific intake just to keep itself warm at these temperatures.
What would happen if: The UK entered an ice age? | WIRED UK
We're heading into an ice age
"One day you'll wake up - or you won't wake up, rather - buried beneath nine stories of snow. It's all part of a dependable, predictable cycle, a natural cycle that returns like clockwork every 11,500 years. And since the last ice age ended almost exactly 11,500 years ago…" (
Ice Age Now)