Four life-sentence prisoners have been behind bars for over 40 years.
The country's longest-serving prisoner is a rapist and murderer who's been in jail for 46 years.
A life-sentence prisoner can apply for parole after 12 years, but many have been in jail for much longer.
There are 362 life-sentence prisoners in jail at the moment - 352 men and 10 women, according to Freedom of Information figures released to the Today FM Newsroom.
65 men have been behind bars for at least 20 years.
11 have been in jail for over 35 years - with four in prison for over 40 years.
The average time a life-sentence prisoner spends in jail has increased in recent years, and in 2020, it stood at 20 years.