Efforts to keep potentially disease-ridden meat out of the UK are being undermined by post-Brexit border checks, a senior health official has said.

The boss of the Dover Port Health Authority said illegal meat, which has not been through proper health checks, was now available on “most high streets” in the UK.

European outbreaks of deadly animal diseases in recent months have left health authorities, Whitehall officials and many in the farming industry worried about the threat they pose to the UK.

But the government has insisted the checks work and it will never “waver in its duty to support the UK’s biosecurity”.

Under the post-Brexit system, checks on commercial vehicles do not take place at Dover itself.

Instead, drivers are ordered to travel 22 miles (35km) away to a border control post at Sevington.

But critics have warned that many lorries are simply failing to turn up for the checks, due to a lack of enforcement.

Parliament’s Environment Select Committee has now launched an inquiry into whether the system is working.

Lucy Manzano, head of the Dover Port Health Authority, told MPs on the committee that the Department for Environment, Food and Rural Affairs (Defra) had been overstating the effectiveness of the system.

She said: “Defra have continually stated that there are robust controls in place. There are not. They don’t exist.”

She added that the department had failed to provide “any confirmation of how food would be controlled at the point it arrives, or more importantly, between the point it arrives and the inspection facility that is accessed 22 miles across”.

Ms Manzano said she had presented evidence to the government “to demonstrate that the system brought in place to safeguard this country from a biosecurity point of view… is not working”.

Defra refused to answer a recent Freedom of Information request from the BBC’s Countryfile programme, asking how many vehicles were failing to turn up for checks at Sevington.

The department claimed that releasing data about Sevington could inadvertently aid criminals looking for weak points in the UK’s border controls.

Ms Manzano claimed illegal meat has now become much more commonplace in high street shops – and that it is becoming increasingly difficult for consumers to spot if the product they are buying has gone through proper health checks.

It is understood that the view inside Defra is that the post-Brexit checks are working as they should.

Earlier this week figures showed that almost 100 tonnes of illegal meat was seized at the Port of Dover last year.

Defra said it is “unequivocal that importing illegal meat products is unacceptable – which is why suspected products are routinely checked at the border to ensure they don’t reach our shores”.

A BBC News investigation last year found that unprecedented levels of seizures had sparked fears of more organised criminal activity.

A similar health check facility to the one at Sevington does exist on site at Dover, but it is understood that the government chose not to use it because of worries about potential traffic queues forming at the border.

Ms Manzano said that decision was “not based on biosecurity” and added that “the very purpose of import controls is to keep the bad stuff out and contain it at first point of entry”.

Last month the UK government introduced strict restrictions on the import of German meat, following an outbreak of foot and mouth disease.

But Ms Manzano said failures in the IT system introduced since Brexit meant that products which should have been undergoing checks were allowed to freely enter the UK for “at least six days”.

When the current system was introduced last year, the government also gave funding to Dover Port Health Authority to carry out spot checks on smaller vehicles directly at the border.

Figures show the vast majority of illegal meat seized in the UK is caught through those spot checks.

But Ms Manzano said that funding was due to run out in seven weeks and that without further government cash the checks would have to stop.

Government discussions are ongoing about how to best fund border checks.

It is understood the decision to put the checks at Sevington has likely had a direct negative impact on how much money goes to the Dover Port Health Authority.

A Defra spokesperson refused to comment on ongoing spending decisions.