Calls for a public enquiry into the state of jails in England and Wales are being made following the death of an inmate.

The union said Government cuts to staff and resources meant the "tragedy" at Pentonville prison in north London was "no massive surprise".

Two inmates are in critical condition in hospital, while two prisoners have been arrested over the attack.

The most recent statistics published by the Ministry of Justice, showed there were 100 apparently self-inflicted deaths in the year to March - the highest for more than a decade.

There were more than 20,000 assaults - 2,813 deemed "serious" - in the 12 months to December, a rise of 27% year-on-year, and nearly 5,000 attacks on staff - a jump of more than a third compared with 2014.

John Attard, PGA national policy officer, said: "It is no secret that we have had concerns about cuts and resources over the last four years. The Ministry of Justice (MoJ) statistics paint a very grim picture indeed.

"Sadly, it comes as no massive surprise to anybody close to this that we have had a tragedy such as this.

"The Prison Service paid staff to leave, the years of experience, the mentoring, the sharing of their experiences - a lot of that has been lost, and it is showing.

"It's why we need an inquiry into this."

The data also showed there were six apparent homicides the largest number for a year to March since current records started in 2000.

There were 32,313 reported incidents of self-harm last year - a jump of 25% on 2014.

In July this year prison officers across England and Wales staged unofficial walkouts amid claims the system was in "perpetual crisis".

It came a month after the MoJ announced nearly £13 million in funds to deal with prison safety issues.