Young offenders jailed following this summer's riots became targets for fellow inmates who were worried about family and friends caught up in the disturbances, inspectors have said.
Nick Hardwick, the chief inspector of prisons, said staff concerns for new inmates led to the number of young offenders put on suicide and self harm prevention forms increasing by 200% at Feltham young offenders institute in west London.
Some young people were introduced to gangs and violence for the first time while others were moved to other institutions more than 200 miles away to make space for more rioters, inspectors said.
The riots became the "primary cause of fights", with those involved being seen by other inmates as responsible for putting other prisoners' families in danger, for damaging their home towns, and for the transfer of their friends to other institutions.
Some young people were even "ostracised by their families due to their involvement in the riots", the inspectors said.
"Some families had told officers that they were thinking of moving home due to their community's animosity towards those who had family members involved in the riots."
Inspectors who visited Feltham on September 12, after August's riots, went on: "Young people already in the prison had negative perceptions of those involved in the riots as they felt that they were responsible for the transfer of their friends to other prisons. They had seen their home areas attacked on television and were worried about family and friends there."
Existing prisoners were moved to prevent disturbances, but "there had been attacks on those involved in the riots and this was now the primary cause of fights", the inspectors said.
They went on: "Young people on different units had formed themselves into gangs and there had been fights between units. This included those who had not been involved in gangs in the community before and who had become part of the unit gang to protect themselves.
"Although there had been no actual self-harming, the number of open ACCTs (assessment, care in custody and teamwork assessments) had increased by 200% due to staff concerns for new young people."