CRIMINALS are using children's chocolate treats to smuggle drugs over a prison wall to ­inmates.

Kinder Surprise eggs are being thrown over the prison wall at Barlinnie Prison in Riddrie, according to a source.

It is understood the drugs are hidden in yellow plastic capsules, normally used to store toys inside the eggs.

A source close to the prison said: "Drugs are being stored inside the Kinder Surprise eggs and then thrown over the prison wall.

"They are usually thrown over at 'exercise time' when an inmate is out in the yard to collect it.

"The switch time and place is organised through contraband mobile phones."

An Evening Times investigation previously revealed the number of drugs seizures in the jail have risen by 176% in the last three years.

So far this year, prison staff have intercepted 127 drug-smuggling attempts at the prison.

Sniffer dogs and intelligence gathering operations are being used to combat the problem of contraband items, according to officials.

Drugs expert and Labour MSP Graeme Pearson said: "Prison officials at Barlinnie will be well used to this kind of practice.

"However, they now have to deal with the additional problem of access to the ­internet and mobile phones.

"This allows a more co-ordinated approach to setting up times and places for the drugs to be put over the wall.

"Prisons are working to combat this by blocking phone signals.

"As soon as this happens, it will be a big benefit in putting a stop to this."

A total of 774 items have been confiscated from cells at Barlinnie since April 1, 2009.

Inmates have also been caught with drug paraphernalia during searches, ­according to official figures released under freedom of information laws.

Prison bosses said the ­increase in number of items recovered was down to the "professionalism and diligence" of staff.

A Scottish Prison Service spokeswoman said: "We ­invest heavily in resources, development of intelligence and working with partner agencies to address the problem of illicit articles being introduced into our prisons.

"Any information brought to our attention is always assessed."

Meanwhile, the number of deadly weapons found in Barlinnie has soared by more than 170% in the last three years.

Knives, razor blades, and homemade weapons has been seized from prisoners.

In total, there have been more than 100 weapons confiscated from cells at HM Prison Barlinnie since 2010 - the vast majority of them makeshift knives.

Warders also confiscated 176 mobile phones and ­related equipment, along with stashes of home-brewed alcohol, and 136 weapons from cells since April 2009.

Thirty sim cards, 18 batteries and 37 chargers were among the mobile phone equipment seized in the same period.

rebecca.gray@eveningtimes.co.uk