For your initial question, why, I think the answer is true of every nation:
If we (humans everywhere) do not wake up and understand that energy is not a resource we can squander, we will be left in a very dire situation very soon. I think the push for more energy efficiency occurs in most developed nations.
How can UK families become more energy efficient? Your answer there lies in small changes: use air drying instead of a dryer for clothes, change light bulbs to energy efficient ones, buy energy star appliances, develop (and FUND) better products (cars, appliances, and more) and research into those products. It's about investment: invest time and money into something and there will be output.