Watch the full report by National Correspondent Rob Osborne
Friends and family of prisoners are worried about their loved ones being locked in their cells for most, if not all, of the day throughout the pandemic.
Rules brought in to protect people in prisons from coronavirus mean visits are more limited and inmates often spend more time in their cells, restrictions the Government's scientific advisory body SAGE says could continue for months.
Campaigners believe this could have dangerous long-term impacts on the mental health of inmates and a negative effect on rehabilitation of prisoners.
A Ministry of Justice spokesperson said throughout the pandemic, their "decisive action has saved the lives of thousands" and inmates are let out of their cells for longer when local restrictions allow.
For 'Maria', not her real name, not being able to see her partner every week throughout the pandemic has been very tough. She was only able to visit him once last year.
"It's been horrible," she said.
"He does phone me very day but it's not quite the same."
She said being kept in a cell for long period of time has had a negative effect on her partner's mental health.
Maria said: "He's telling me about being locked up all the time and it does get to him.
"He gets on very well with the prison officers which does make life a lot easier for him but it's not fun being sat in a cell."
While prison is not designed to be easy for inmates, Amnesty International warn the impact of keeping people inside for such extended periods of time could have negative impacts on society in the future.
Dr Dennis Eady, who works with the human rights organisation Amnesty International, said it is difficult to imagine the drastic impact being confined to a cell for so long could have a on a prisoner's mental wellbeing.
"We're all conscious of mental health problems in the community as a result of Covid but imagine being locked in a concrete box for 23 hours a day for over a year.
"It's hard to imagine what kind of situation people will be in when they emerge...those that are released, will they emerge with any kind of sanity at all? Will they emerge with a hatred for society for the way they've been treated?"
In response, a Ministry of Justice (MoJ) Spokesperson said: "Our decisive action has saved the lives of thousands of lives in custody during the pandemic.
"Prisoners are let out of their cells for longer wherever local restrictions allow."
The MoJ also said it has made prisoners' wellbeing "a priority" and taken several steps in direct response to the pandemic. These include rolling out video-call technology to all prisons, increasing access to mental health support from specially trained staff and providing inmates with extra phone credit so they can keep in touch with loved ones.
Different prisons will have different regulations and restrictions around visitation during the pandemic.
SAGE says these restrictions could remain in place for months to come, unless there is faster vaccination rollout for staff and inmates.
From March 2020 to the end of April 2021, 143 inmates across UK prisons have died with coronavirus. Of those, 116 were suspected or confirmed to be caused by Covid. A further 47 probation service users have died with the virus since the start of the pandemic.
More than 16,000 prisoners or children in custody have tested positive for the virus across 127 UK sites.