Image copyright PA Media Image caption HMP Birmingham, also known as Winson Green prison, is the only institution given the lowest score which was not entirely publicly-run last year

Nearly one in seven prisons in England and Wales have been judged to have a performance of "serious concern" - the highest proportion since ratings began.

Sixteen prisons (14%) were given the lowest score in the ratings, which are published annually by the Ministry of Justice (MoJ).

The MoJ also revealed a record number of assaults in prisons and on prison staff in the year to the end of March.

Responding to the report, the MoJ said it is spending an extra £70m on safety.

All of the 16 prisons or young offender institutions to be given the lowest performance in 2018-19 are publicly-run, although HMP Birmingham was operated by private company G4S during some of the period.

The performance of a further 28 prisons - again all publicly-run - was said to be "of concern".

Of the private sector prisons, 12 were given an "acceptable" grading and one, Ashfield, was rated "exceptional".

Fourteen publicly-run prisons were also given an "exceptional" grading.

The 16 prisons or young offender institutions given the lowest performance rating of "serious concern" in 2018-19 were:

Aylesbury

Bedford

Birmingham

Bristol

Chelmsford

Feltham

Liverpool

Mount

Nottingham

Onley

Pentonville

Portland

Rochester

Wandsworth

Winchester

Wormwood Scrubs

The MoJ report also showed there were 34,425 assaults in prisons during the same period - an increase of 11% from the previous year.

It also revealed 10,311 reported attacks on staff - the highest since comparable records began.

Of those, 1,002 assaults were classed as "serious - an increase of 12% from 2017-18.

The MoJ report also found self-harm incidents reached an all-time high of 57,968 incidents in the 12 months to the end of March 2019 - an increase of 24% on the previous year.

Separate data from the Office for National Statistics (ONS) showed male prisoners were 3.7 times more likely to take their own lives compared with the general population.

In the 12 months to June 2019, there were 309 deaths in prison custody, a decrease from 311 deaths the previous year.

Of these, 86 deaths were self-inflicted, up from 81 the previous year.

Meanwhile, new Home Office figures show armed police incidents increased by 7% to 20,186 last year.

Officers' guns were discharged in 13 incidents in the year to March 2019 - up from eight in the previous 12 months.

That is the highest number since the current recording system began in 2008-2009.

Responding to the findings, the MoJ said levels of violence, self-harm and suicide were "unacceptably high" at many prisons.

A spokeswoman added: "That is why we are spending an extra £70m to improve safety and decency, have recruited more than 4,700 more prison officers since 2016 and introduced the key-worker scheme - giving officers time to build the vital relationships that change lives and increase stability.

"It will take time for improvements to be seen across the estate but we remain determined to make progress and will continue to prioritise this important work."