Rihanna's tunes a hit behind bars
Rihanna is top of the prison charts after it was revealed she is the most popular female artist among British prisoners
The late rapper Tupac - who was no stranger to life behind bars himself after serving 10 days for beating another musician with a baseball bat - was named the most popular overall artist in British jails, NME.com reported.
Rihanna, who was fourth, was the only female artist in the top 20. Her ex-boyfriend, Canadian rapper Drake, was the fifth most requested.
Jamaican dancehall artist Vybz Kartel came second and rapper K Koke third.
Other artists to feature in the top 20 included Akon, Metallica, Slipknot, Eminem, Lil Wayne and UB40.