Mounir Lameche worked as a school caretaker under a fake name and fraudulently used an Italian passport to pass a DBS check.
The 48-year-old was arrested after a DBS application was made under the name of Adel Boughamouz, which the court heard was a “false name” used by Lameche.
Prosecutors told how Lameche had obtained employment at Beechwood School in Slough after passing the DBS check with his false documentation.
Maria Culling, prosecuting, said: “He would not have got that employment if the documents were not false.”
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Police searched the address of Lameche, of Sussex Place in Slough and found two French passports, an Irish passport and a French national ID card all in the name of Boughamouz.
Also at the address was another illegal immigrant, Amine Lameche, who also had a fake ID document, a Belgian driving licence in the name of Amine Ziani.
Lara Simak, defending, claimed both defendants might be allowed to stay in the UK because they had been continuously resident in the UK for over 20 years, after arriving from Algeria illegally.
“They do get a statutory right to remain in the UK”, the barrister said.
The court heard the Home Office had already refused Mounir Lameche’s application to remain after finding he had been unable to establish he had been continuously resident for 20 years, but he was appealing.
Amine Lameche, 53, had an outstanding application.
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Both defendants had been paying taxes for the past 20 years under their false identities, Ms Simak explained.
The barrister said the impact of the defendants being sent to prison would be “catastrophic” on their applications for the right to remain in the UK.
Ms Simak said Mounir Lameche accepted he had been using his false documents to remain in his job as a school caretaker for the last 20 years.
“There is no benefit for it above simple employment and surviving on that employment”, the barrister added. “It is necessary to survive. An illegal migrant in the UK for 20 years is expected to work to survive.
“He was not a person who had a criminal past or something to hide other than his immigration status.
“I appreciate that a risk could have arisen, the risk did not arise because he is not a dangerous person.”
The defendants could not be punished at the hearing because Reading Crown Court heard the prosecution believed Mounir Lameche was an overstayer, meaning the judge would be forced to jail him.
The defence disputed this and the case was adjourned until February 3 so checks could be made.