Thirty years in prison is currently the most severe punishment available in the UK legal system.From The Telegraph.
About 12% of state prisoners in the U.S. and about 3% of federal prisoners in the U.S. are serving life sentences. A significant additional percentage of state prisoners and about 10% of federal prisoners are serving terms of twenty years or more.
In Colorado, habitual offender sentences for most serious crimes, first degree murder, first degree kidnapping, child abuse or neglect causing death, and most serious sex offenses carry sentences of 30 years or more, and with consecutive sentences, terms of thirty years or more for other serious crimes aren't too unusual. Many drug offenders and child pornography offenders likewise are sentenced to more than thirty years in prison.
Of course, the U.K. has a much lower murder rate than the U.S. despite this fact, although crime rates for many other crimes in the U.K. are comparable to those in parts of the U.S.