A father was jailed for 13 months yesterday after he conned the benefits system out of nearly £80,000 for 36 fictitious children.

Irvin Fraser, 30, admitted claiming the child tax benefits over a period of three years from two addresses in Aberdeen. Inland Revenue officials sent the unemployed father-of-two £79,718 of taxpayers' cash without checking for birth certificates. His scam went undetected even when he made duplicate claims for four of the children.

Sentencing Fraser at Aberdeen Sheriff Court yesterday, Sheriff Alexander Jessop said: "It appears no checks were made on the claims, but this does not justify fraudulent activity by making claims for 36 fictitious children resulting in sums of money being paid into your bank account for the benefit of your lifestyle.

"It seems to be appropriate that you be sentenced to a period of imprisonment."

Prosecutors accepted a not guilty plea by co-accused, Annette Fraser, 37.

The court heard the scam started after a friend told Fraser how easy it was to fake a claim over the phone. He spent up to £200 a day on heroin and needed cash to feed his addiction.

Fraser admitted making the fraudulent claims in writing and over the phone between November 2003 and June 2006. The claims were made in four different names and began with a claim for an extra two children. All the payments were made into the same bank account.

By September 2005 he was claiming for 14 children, spiralling to 36 by the time he was questioned by HM Revenue and Customs investigators.

Fiscal Gulnaz Bari told the court: "All the monies from these claims were paid into the account of Annette Fraser, the partner of the accused. Investigations were being carried out to reaffirm the veracity of the claims."

Sheriff Jessop asked: "You're saying the accused made up names - this seems to have gone on from 2003 to 2006 - he just called up and added the children's names?"

She replied: "Obviously it wasn't checked because the cheques were sent to the accused."

Fraser's defence solicitor Shane Campbell said: "Someone had indicated to him that he had made such a claim that was false and this resulted in a payment being made. That seems to have sown the seed in the mind of Mr Fraser."

Fraser earlier admitted making fraudulent claims between November 1, 2003 and June 29, 2006. He previously explained: "I was claiming child tax credit for my son and just added another name by chance. They never asked for any documents. It went on for two years and I got away with it.

"I couldn't understand why they did not pick up on it. How could someone claim to have so many children but not be old enough to have them?

"I wanted to stop but it just snowballed and spiralled out of control. I withdrew my last claim but they still paid £4000 into the bank account. I stupidly spent it, and that's when I got caught."

Fraser went on spending sprees buying clothes, toys and other products to "spoil his children rotten". He also spent £25,000 on his wedding at Duthie Park's Winter Gardens on August 27, 2005.

Anne-Marie Gordon, HMRC Assistant Director of Investigation in Scotland, branded the fraud as a "premeditated attack on the tax credits system".

She said: "Making fraudulent tax credit claims is not a victimless crime and he had little consideration for the public purse or the individual whose identity he used to commit this fraud.

"The vast majority of tax credits claimants are honest and claim only what they are entitled to, but those who believe that they can cheat the system without consideration or second thought should think again.

"The sentence reflects the seriousness with which the courts take this type of offence."