Inspectors described 'very poor' living conditions at Wandsworth and 'piles of litter'
In the Annual Prison Performance Ratings for 2022/23, published in July, Wandsworth was among nine rated as a "serious concern".
Its overall performance score, based on a range of measures including security, rehabilitation and training and expressed as a proportion of 100%, was 46.4% - one of the lowest out of all 119 prisons.
Wandsworth was handed the same "serious concern" rating in 2016/17, 2017/18 and 2018/19.
Inspectors described "very poor" living conditions with "piles of litter" and said levels of violence had risen since previous inspections.
The IMB said a "staffing crisis" and "crumbling" Victorian buildings were "at the heart" of the prison's problems.
In findings published in September 2022 the body, made up of volunteers tasked by ministers to scrutinise conditions in custody, highlighted the "negative impact" of staff shortages and "wholly inadequate physical conditions".
The IMB said: "Significant staffing problems are adversely affecting the delivery of a consistent regime."
Although "technically fully staffed", more than 30% of staff are "non-operational on a regular basis, for a number of reasons", sometimes rising to more than 40%, according to the findings.
The "recruitment, training and retention" of skilled and well-motivated staff is "essential" amid a rise in "volatile young prisoners" and "alarming" levels of violence but the board said it was "very concerned that this is not happening".
Tim Aikens, chairman of the prison's IMB, said at the time: "The board is once again expressing its concern about conditions in HMP Wandsworth, whose Victorian buildings are long overdue significant investment.
"With depleted staff numbers, degrading living conditions and high levels of mental health need, the increasing level of violence is both unsurprising and deeply worrying."