A wing at Doncaster Prison was evacuated last night after a fire in a cell.
Fire crews from Doncaster and Adwick stations were called to the Marshgate jail at 8.30pm and found one of the cells well alight.
The rest of the wing was badly affected by smoke and prison officers evacuated it.
The inmates in the cell were not injured and there were no casualties.
The fire is believed to have been started deliberately, said a fire service spokesman.