The smuggling of drugs and weapons into jails is "unacceptably high", a report by the chief inspector of prisons said on Thursday.

Brigadier Hugh Monro also called for an overhaul of the drug-testing regime in jails as he launched his first annual report since taking over the post last year.

The prison system is operating "safely and effectively" on the whole, the chief inspector found, with staff singled out for their professionalism and commitment.

But he admitted that the issue of contraband materials must be addressed.

He said: "The smuggling of drugs, mobile phones and weapons into prisons remains unacceptably high. This activity makes prisons less safe, enables criminal activity to continue and causes bullying and intimidation."

Brig Monro said today it is "critical" that prisons are safe and secure, adding: "Why should illegal drugs be smuggled into prison and, indeed, why should we allow illegal communication devices into prison which allows criminal activity to continue based in prison?"

The issue has been raised with prison service chiefs, who are looking at ways to improve security, the inspector added.

An average of 17.5% of prisoners test positive for drugs upon release, the report found.

Brig Monro said: "It seems wasteful to spend public money on addiction programmes when security breaches are simply allowing drug use to continue."

The report also said an overhaul of the drug-testing regime is needed to provide an accurate picture of the problem in all prisons and identify the drugs being taken.

Brig Monro went on: "A sensible drug-testing regime, which I don't think we have at the moment, needs to be put in place to give us a better and more accurate picture."

The inspector also questioned whether there should be more "proactive" efforts to get addicts in jail using the heroin substitute methadone to reduce their dosage.

Methadone should be given in tandem with treatment from addiction staff in prison, Brig Monro stated.

A national strategy is also called for in relation to the preparation of prisoners for release, with concerns raised that current guidance on re-offending is "fragmented and piecemeal".

Concern was raised that the practice of 'slopping out' remains at Peterhead prison and this is branded a "significant risk". The issue is set to be highlighted in a forthcoming report.

But extensive redevelopment work across the prison estate means conditions for inmates and staff have improved.

Further concerns were also raised about conditions at Stirling's Cornton Vale, the country's only women's prison, after a report earlier this year found it was in crisis.