Two members of an organised crime group, who attempted to claim £10.2 million in tax credits using stolen identities of public sector employees, have been jailed for a total of eight years and nine months.

IT support worker Kayode Sanni, 38, was living in Moorland Road, Pudsey, at the time of his arrest in March, 2012. Sanni was found guilty of his role in the conspiracy at the Central Criminal Court on June 26 and was yesterday jailed for five years and three months at the same court.

Meanwhile, Oluwatobi Odeyemi, known as Emmanuel, of Palmer Avenue, Gravesend, Kent, was jailed for three and a half years.

They were brought to justice after a complex criminal investigation by HM Revenue and Customs.

Two women, Adedamola Oyebode, 30, of Knapmill Road, Lewisham, London, and Chantelle Charmaine Gumbs, 34, of Francis Street, Leeds, have been given suspended sentences.

The court heard that Adedamola Oyebode worked as an events and marketing assistant for the Civil Service Sports Council (CSSC). In April and June 2009, she accessed the CSSC’s password protected membership system and stole personal details of 10,300 members.

Oyebode then passed the data to her brother-in-law, Oluwatobi Odeyemi, who was a key facilitator in the criminal operation, managing the stolen data used to make false tax credits claims.

Emmanuel Odeyemi’s friend, Kayode Sanni, ensured the stolen data was used to apply for tax credits. He recruited and managed a friend, Gumbs. Her job was to request the tax credits application packs from HMRC used to make fraudulent tax credits claims. The gang completed the forms, adding details of bank accounts that had been set up to commit the fraud, and returned them to HMRC.

Investigators believe the fraudsters conspired with two others who are on-the-run, and are appealing for information on their whereabouts. Emmanuel Odeyemi’s brother Oluwagbenga Odeyemi, known as Stephen, 39, and Stephen’s wife Oluwatumininu Banjo, 40, also known as Tumi, are thought to be in Nigeria. The couple used to live in Dagenham, Greater London.

Simon York, Director of HMRC's Fraud Investigation Service, said: “These criminals launched an organised attack on the tax credits system, a system designed to help some of the most vulnerable people in our society.

“Thanks to the experience of HMRC's officers, the effectiveness of our counter-fraud checks, and an extremely complex criminal investigation, the fraud was stopped and HMRC prevented £8 million of false claims being paid to the criminals.

“We will continue to tackle those committing tax credits fraud and ask anyone who has information about the two Nigerian citizens who may be connected with this fraud to call the HMRC Fraud Hotline on 0800 788 887.”

The scam was uncovered in late 2009 by HMRC’s identity fraud and risk teams concerned about the volume of new claims for civil servants, predominately for working tax credits. Their initial enquiries also highlighted potential sources of a data leak. HMRC began a criminal investigation in April 2010 and through detailed forensic analysis, investigators uncovered the fraudsters, pieced together the scam, and identified the extent of the CSSC data loss.

HMRC’s investigators analysed huge amounts of information, including tax credits records, recordings of phone calls to the tax credits helpline, banking data, notebooks, diaries, computer, email, and data storage devices, and mobile phone, text message and telephone records. An expert voice analyst gave evidence during Kayode Sanni’s trial.

Of the 10,300 identities stolen, 2504 were used to make fraudulent tax credits claims resulting in £2.4 million being paid out. Further claims were made but not paid. Had the fraud not been uncovered and stopped, it is estimated that at least another £7.8 million would have been paid to the criminals, leading to a total attempted fraud of £10.2 million.

Sentencing the fraudsters at the Old Bailey, His Honour Judge Dodgson, said: “It was a serious fraud that you all involved yourselves in”, adding to Sanni who stood trial, “the only remorse is that you got caught.”