Landlords and agents could be inadvertently granting assured tenancies rather than the Assured Shorthold Tenancies they had intended.

It means that they will always be unable to use Section 21 notices for repossession.

Judgment in a court case last year has led to what could be ‘thousands’ who thought that they had complied with the law – but now find that they haven’t.

Furthermore, attempts to put right a simple administrative error would be out of the question.

In last February’s case, Caridon Property Ltd v Monty Shooltz, it was ruled that a landlord who failed to give the tenant a current gas safety certificate before the start of the tenancy, could not put it right by issuing it after the tenancy began.

The judge ruled that under the Deregulation Act 2015, failure to issue a gas certificate before a tenancy begins invalidates any subsequent Section 21 notice. The mistake cannot be corrected.

In Caridon Property Ltd v Monty Shooltz, District Judge Bloom ruled that because the tenant had only been served a gas safety certificate 11 months after the tenancy began, a prescribed requirement had not been complied with.

The landlord had served a Section 21 notice on the tenant, but the Judge ruled this invalid.

This decision was appealed and heard, again in a county court, by Judge Jan Luba, who also decided that the prescribed requirement had not been complied with and, importantly, could not be rectified by subsequent service of the certificate.

Normally, rulings in county courts are not treated as binding or as legal precedents.

However, Judge Jan Luba is a respected, recognised authority on housing law. Before becoming a judge he had been one of the country’s leading housing barristers.

Not only that, but he co-authored a textbook, Defending Possession Proceedings, which most district judges use when deciding how to apply the law.

In other words, his ruling in Caridon Property Ltd v Monty Shooltz is likely to be considered definitive by other courts.

Until the case, landlords – and agents – who had failed to issue a gas safety certificate at the prescribed time, would do so later on before serving a Section 21 notice.

Following last year’s case, the legal community and landlord bodies had widely expected the Government to address the issue by amending the AST and Gas Safety Regulations, arguing that it had never been intended to impose such draconian requirements on landlords.

The current Gas Safety Regulations state that new tenants must receive “a copy of the last record made in respect of each appliance or flue” before occupation. However, the AST Regulations state that the time limit does not apply.

The National Landlords Association says that its advice line is being inundated, and that it has lobbied the Government for clarification for over a year.

NLA chief executive Richard Lambert has now heard that the Government does not intend to address the ruling.

Instead, the Ministry of Housing, Communities and Local Government will update its guidance on the Gov.uk website.

Lambert said: “Having pressed the Government to respond to this judgement for nearly a year, their answer seems to be, ‘We’re not that bothered’.

“The ministry clearly doesn’t understand the impact it is having.

“The NLA Advice Line is taking more and more calls from landlords who thought they had complied with the law and now find themselves facing a disproportionate penalty for an administrative error. We cannot believe this is what Parliament actually intended.

“The NLA recognises the vital importance of ensuring landlords arrange an annual gas safety check with a Gas Safe engineer.

“But we do not support the de facto introduction of assured tenancies because landlords cannot rectify an unwitting error made before a tenancy begins.

“We have no intention of letting this rest and will continue to lobby for change.”