A council housing officer who faked documents to secure properties for illegal immigrants in one of the biggest-ever frauds of its kind is facing jail.

Ibrahim Bundu, a homelessness case worker at Southwark council, also created false identities to obtain houses for friends and family including his mother and ex-wife, forging references and medical letters to push them up the waiting list.

His “audacious” fraud was uncovered when auditors carried out an investigation into a housing application in 2011. They found that every document used to support the request was fake.

The team uncovered a paper trail of forged references and medical letters stretching back three years which resulted in 23 homes being given to bogus applicants, conning the council and the 20,000 on one of Britain’s longest waiting lists in genuine need of social housing out of properties.

Subsequent checks, via the UK Borders Agency and HMRC, revealed that a number of the applications had resulted in council homes being allocated to people not legally allowed to be in the UK.

Bundu made his applicants high priority, in at least one case pretending a single woman was pregnant.

Fifteen of the properties have been recovered and the remaining eight will be reclaimed now the fraud case has ended.

House prices in Southwark average £460,000, putting the total value of homes handed out at more than £10 million. Bundu, of Peckham, pleaded guilty to misconduct in a public office and transferring criminal property at Woolwich crown court last week. The charge carries a maximum sentence of life imprisonment.

Six co-defendants, including his mother Marie Bundu, ex-wife Ada Kamara, estranged wife Farmata Koroma and Ms Koroma’s aunt Haja Sesay, admitted obtaining property by deception. Bundu also made false applications for health worker Aminata Lassayo and restaurant manager Rebecca Quartey, who paid him in cash to secure them a home. He also pleaded guilty to theft.

Southwark council said the fraud was “one of country’s biggest cases”, adding: “He used fake documents to support the fictional applications, making them very hard to trace at the time.”

Ian Wingfield, deputy leader and cabinet member for housing management at Southwark council, said: “Southwark has one of the longest waiting lists for council housing in the country, and that’s why we have to make sure everyone who has a council home is genuinely entitled to it.

“Public sector fraud is not a victimless crime. It can take homes away from people who need a roof over their heads.”

Richard Livingstone, Southwark’s cabinet member for finance and resources, said: “This shocking case shows how in the past some criminals were able to abuse the system for their own gain.

“I’m pleased to say that this is much harder since we clamped down hard on fraud, introduced passport scanners to help identify fake documents, and started using ever more intelligent data checks to uncover anything suspicious.” Bundu and his co-defendants are due to be sentenced next month.