Letting agents were secretly filmed by the BBC accepting fake IDs from tenants, with innocent firms said to be “easily duped” into thinking that the paperwork was authentic.

Last night’s Inside Out London exposed how Right to Rent rules have created a black market in forgeries that helps undocumented immigrants flout the law.

The programme said criminal gangs are faking paperwork including passports, National Insurance cards and residence permits, selling them for up to £500.

A BBC undercover reporter, Zack Adesina, used a hidden camera to record deals with the fraudsters.

The forged IDs were then presented to letting agents, who seemingly accepted them without question as proof of a tenant’s Right to Rent, the BBC reported yesterday.

Last night’s programme showed one agent,un-named, appearing to accept the paperwork.

Adesina said that the counterfeit passports he saw and acquired were “remarkably convincing” with some even featuring mock biometric imprints.

However, they would not pass close inspection, for example at airport controls.

Landlords – and agents fulfilling the Right to Rent obligations on their behalf – face criminal sanctions of up to five years in prison and unlimited fines if they are found letting to someone who does not have the right to live in the UK.

Housing specialist David Smith, of law firm Anthony Gold, said: “They do not have the knowledge or skills to do the job properly.

“I’ve never met a landlord who can tell a valid Lichtenstein passport from a forgery.”