Do note that the UK is 15.6x as dense as Finland, and the climate is quite different: e.g. in Helsinki (southermost city) mean daily temperature is below freezing point 4/12 months of the year (very consequential for driving). E.g. in Scotland even the mean daily minimum does not cross freezing point in any month.
OECD data has Finland at 0.36 fatalities per 10k vehicles vs 0.41 in the UK.
At least in the countryside a stereotypical summer month death is one where bunch of young men go to a party with their old BMW or Merc, and then drive back in middle of the night at a crazy speed and hit a tree. Bonus points for the driver being drunk/on drugs and nobody wearing seatbelts.
There is even a popular racing class called "jokamiehenluokka", where drivers are obliged to sell their cars for 2000 euros if somebody makes an offer. That rule is designed to keep the barrier of entry low, as drivers don't have the incentive to invest too much into their car. Apparently you can take the exam tojoin at age of 15, which is 3 years before the normal minimum age for driving license.
I recommend the game "My Summer Car" for those interested in all this culture.