Prisons including HMP Leeds in Armley to be put into "immediate lockdown"

The POA said it "praised the decision of the Secretary of State for Justice and the Director of Public Sector Prisons for their decision to place Prisons in England and Wales on immediate lockdown".

According to the union, restrictions inside jails will mean:

- Inmates generally being locked up but allowed to access showers, phones and exercise - with social distancing restrictions in place

- Prisoners who carry out kitchen, cleaning and laundry work can continue

- No social visits

In a statement, the POA also claimed prisoners due at court "will be discharged to attend unless the courts service advise us otherwise".

In a tweet, the Ministry of Justice (MoJ) said: "We have suspended all prison visits in England and Wales for today.

"This is while we ensure safe and secure functioning of our prisons while enforcing social distancing.

"If you have a visit booked today, please do not attend."

Downing Street said there were "robust and flexible plans" to keep staff and prisoners safe.

Prisons and the Ministry of Justice were examining how the social distancing rules could be complied with.

The Prime Minister's official spokesman said: "We do recognise the importance of continued contact with family."

Meanwhile, the University and College Union (UCU) has called for face-to-face prison education to be suspended, raising concerns about workers' safety.

A small-scale poll conducted by the union found that 63% of prison education staff said hand washing facilities are inadequate, while 64% said classrooms are not cleaned between lessons and 93% said they are expected to share equipment, such as pens and keyboards, with other staff and prisoners.

UCU general secretary Jo Grady said: "Education has a vital role to play in prisons, but we must ensure the safety of staff and prisoners first and foremost, and do everything possible to limit the spread of the coronavirus. We want to work with the prison service to look at ways to get alternative learning materials to prisoners, but the face-to-face teaching must end for now.

"It is unacceptable that prison education staff are being asked to share equipment, work in dirty classrooms and undertake extra duties."