Inmates harmed themselves hundreds of times while behind bars at Winchester Prison in a year, figures reveal.

Prisoners self-harmed at least 592 times in the 12 months to September 2020, a decrease from 821 times the year before, figures from the Ministry of Justice show.

At least 46 of these incidents were serious enough to warrant a hospital visit

Cutting, drug overdoses and attempted hanging are among cases that must be logged as self-harm by staff at the facility, which housed around 484 people that September.

Incidents across England and Wales have declined since a record high was reported in the year to September 2019, but latest figures from the MoJ show a quarterly increase at Winchester which recorded 154 cases between July and September, compared to 140 the three months before.

The MoJ says that the most recent figures reflect an exceptional time, given the impact of the Covid-19 pandemic on the prison population, while experts believe prison lockdowns and enforced solitude could be contributing to mental distress behind bars.

In an effort to contain coronavirus, facilities have introduced more restrictive regimes, with visits limited or suspended and movement of prisoners restricted.

The Howard League for Penal Reform said the severity of the regimes meant tens of thousands of people had spent hours – up to 22 a day – in their cells, forced to endure solitude in “grim conditions”.

Chief executive Frances Crook said: “The mental distress caused by isolation can affect people in many different ways, some of which may not be evident for months or years.”

Prisons and Probations Minister Lucy Frazer said prison staff had put tremendous effort into keeping inmates safe but acknowledged that the increased restrictions were “extremely tough” for them.

She said that although self-harm had started to fall before the pandemic, it was important to be “more vigilant than ever about providing support in this incredibly challenging period”.

Across prisons in England and Wales, there were 58,870 incidents in the 12 months to September last year, 2,843 of which required hospital attention.

That was down by 5% on the previous year, reflecting a 7% decrease at male establishments but an 8% increase at female prisons.

However, the latest quarterly figures show a stark 24% increase for women and a 5% increase for men.

Across England and Wales, the rate of incidents now stands at 595 per 1,000 male prisoners and 3,557 per 1,000 female.

At Winchester Prison there were an estimated 1,223 incidents per 1,000 inmates that year, based on the latest population figures.

The figures show that some of those who self-harm do so multiple times, with men likely to harm themselves on average 4.2 times each, compared to 10 times each for women.

The true scale of the issue could be greater, given that monthly figures of less than five are suppressed by the MoJ.