Concerns over attitudes of staff at a south London jail towards inmates have been raised by the prison watchdog.
Wandsworth jail has 1,456 inmates
Almost twice the average number of inmates had complained of victimisation at Wandsworth prison, a report showed.
Chief Inspector of Prisons Anne Owers said inspectors witnessed "poor" and "abusive" behaviour by staff towards inmates during a visit in July.
The Prison Service said the prison faced "substantial" challenges but was confident it would continue to improve.
Hit and kicked
The report made 160 recommendations for improvement at the category B prison which houses 1,456 inmates.
It found that almost half of all of those interviewed said they had been victimised by staff, compared with the national average of 24%.
And 12% said they had been hit, kicked or assaulted by staff, which is three times the national average.
Black and Asian prisoners were found to be more likely to report staff victimisation but few of those complaints resulted in action by senior management.
Ms Owers said: "This is an inspection of an improving prison but one which has a significant way to go before it is a good and well-performing prison.
"The most significant barriers to change are the constant and increasing population pressure, and the approach and attitude of some staff."
But she added that the progress made in some areas of the prison showed what can and needs to be achieved.
Cleanliness, hygiene and food had got better, prisoners had more time out of their cells and first night and induction arrangements had improved, the report said.
Prison Service director general Phil Wheatley said: "The governor and management are continuing to ensure that staff behave appropriately at all times.
"A robust approach is being taken with those who fail to maintain high standards," he added..