Male and female prisoners should be given free condoms as part of measures to halt the spread of HIV and hepatitis in UK jails, two charities have said.
Hepatitis C levels in prisons are 20 times higher than among the public
Prison healthcare is inconsistent and often sub-standard, said the Prison Reform Trust and National Aids Trust.
Over half of prisons have no sexual health policy despite HIV and hepatitis C being commonplace, the survey of prison healthcare managers found.
But the Home Office defended its record on providing prison healthcare.
Researchers found hepatitis C levels in prisons are 20 times higher than the rate in the general public, with 9% of male inmates and 11% of women infected.
And HIV rates in male prisoners are 15 times higher than those of men not in jail.
Prisoners do not have appropriate access to condoms, disinfecting tablets, clean needles or healthcare information, the report said.
Meanwhile, some prisoners believe they will be subjected to bullying and discrimination if their health status is known.
Providing free condoms to prisoners was just one of a host of recommendations in the report.
It also called for better training for healthcare staff, a national framework for prevention, treatment, care and support and regular anonymous blood tests to establish levels of HIV and hepatitis C infection.
But the suggestion of free condoms for prisoners has been condemned by the right-wing Conservative Way Forward group.
Its spokesman Andre Walker told the BBC: "Most people who've been victims of crime don't expect prisoners to be going into jail and having sex and getting involved in relationships.
"I think it's entirely unacceptable and the encouragement of it is pretty wrong in the eyes of most right-thinking individuals."
Meanwhile a Home Office spokesman defended the Prison Service's record on providing good healthcare for prisoners.
He said the Prison Service had been working with the Department of Health since 2000 to enable inmates to have similar access to healthcare as the wider public.
"Our current strategy for preventing the spread of communicable diseases in prisons covers training, education prevention, risk reduction and harm minimisation," he said.
The report findings are due to be presented to ministers at the Home Office and Department of Health, as well as the Prison Service in Scotland and Northern Ireland.
The stance adopted by the Prison Reform Trust reflects the fact that responsibility for prisoners' health is due to transfer from prisons to the NHS in April 2006.
Ms Lyons said: "Courts sentence people to custody, not to inadequate healthcare.
"It is time the NHS developed good, well resourced policy and practice to tackle blood-borne disease in prison.
"Anything else would amount to double punishment and lead to a public health risk.
"Now is a good time to put these reforms into place with prison health services being taken over by the NHS."