The current rate of inmates taking their own lives at the Acklington jail is confirmed in data released by The Howard League for Penal Reform.
So far this year, three people have killed themselves at the male-only Category C unit, compared to one suicide in each of 2015, 2014 and 2013.
The figures are part of statistics which show that 102 prisoners have committed suicide in prisons in England and Wales during 2016, which is an all-time high since records began in 1978. The previous highest was in 2004, when 96 deaths were recorded.
A prison spokesman said: “Death in custody is a tragedy, affecting families, staff and other prisoners. We work with the prisons and probation ombudsman and the police to investigate deaths in our care.”
Berwick MP Anne-Marie Trevelyan said prison suicides were concerning.
She added: “Prison is a punishment, but it is also an opportunity to rehabilitate offenders and to help them become prepare to be productive members of society on and part of that is providing support for mental health issues.
“Our prison staff are tackling so many issues within our prisons, something that I am continuing to raise with ministers, particularly in relation to HMP Northumberland.
“I was pleased to see £500million of additional funding in the Autumn Statement for prison safety, enabling the recruitment of 2,500 extra prison officers.
“I hope to see an improvement to the present regional contract, which at HMP Northumberland means not enough treatment is available.
“Improving prison safety is vital to protect officers and to enhance the welfare and mental-health of inmates.”
Earlier this year, an Independent Monitoring Board Report for 2015 showed that the number of self-harm and violent incidents had risen at HMP Northumberland.
It stated that ‘self-harm was a worry’, but the Board was ‘impressed with the caring way that individual incidents of self-harm are handled’.