Holyrood's health committee has demanded prisoners have access to the same standard of healthcare as the general public.

The parliamentary report concluded the NHS has "under served" the prison population since it took over the healthcare responsibility of prisoners in 2011.

It also says promised improvements have not materialised and the will to make necessary changes quickly has been "conspicuous by it's absence".

MSPs have now called for Scottish ministers to set out plans to get the healthcare of prisoners, of whom 70% are estimated to have mental health problems, on par with that of the wider community within two years.

The inquiry revealed up to 50% of clinical time is being wasted due to missed appointments, which often are a result of difficulties arising when transferring inmates to prison health centres.

With the number of over-50s behind bars increasing by 50% in the last five years, the report also highlighted the complex health and care needs of the ageing prison population.

The report said: "The overriding impression we have received from our evidence is of a population which has been very much under-served by the change in responsibilities.

"We do not accept the suggestion or expectation that progress and change within the health service takes a long period of time.

"It does not need to if the will is there and sadly within prison healthcare this has been conspicuous by its absence at senior management levels."

The report has urged the Scottish Government to prepare a strategic plan setting out "how the aims of parity of healthcare within and outwith prisons will be fully met within the next two years".

Committee convener Neil Findlay said: "The point of transferring prison healthcare from the prison service to the NHS was to ensure prisoners receive healthcare equivalent to that of the wider community in Scotland.

"It also offered a unique opportunity to address health inequalities within the prison environment so it's disappointing to discover that that opportunity is not being taken up.

"The fact that missed appointments are accounting for 50% of clinical time represents a waste of resources that needs to be addressed through better joint working between the SPS, health boards and contractors."

Public health minister Aileen Campbell said: "We welcome the health Committee's work and will carefully consider the report's recommendations as we work with partners to take this forward.

"We are dedicated to increasing the consistency of care across Scotland's prisons.

"We are already working to make improvements across a range of issues that the committee has explored, including through-care, substance misuse and mental health.

"However, we recognise that more can always be done."