The Special Criminal Court has described as bordering on the absurd Frederick 'Freddie' Thompson's claims that he had a constitutional right to privacy when captured on CCTV cameras on the day he is accused of a murder.

The three judges were delivering their ruling on a defence application to exclude the private CCTV footage, which the State says links him to the murder of shoe shop manager David Douglas on 1 July, 2016 on Bridgefoot Street in Dublin.

The 37-year-old, with an address at Loreto Road, Maryland in Dublin, has pleaded not guilty.

The non-jury court has heard that the 55-year-old was shot six times shortly after 4pm, as he took a meal break at the counter in his partner's shop, Shoestown.

A semi-automatic pistol with its serial number removed was found next to his head.

The prosecution does not argue that Mr Thompson carried out the actual shooting, but the three judges have heard that his DNA was found in two alleged 'spotter' cars used in the shooting.

Two detectives also identified him in CCTV footage as the driver of one of the cars and walking across Meath Street that afternoon.

Michael O'Higgins SC argued that this and other footage of his client in a restaurant breached his right to privacy, as it was obtained unlawfully by property owners, who had not registered their systems with the Data Protection Commissioner.

Justice Tony Hunt, presiding, read from their ruling this morning. He said that he and his colleagues did not accept that the nature of the activities that the State sought to associate with the accused could give rise to any expectation of privacy on his part.

"Such claims border on the absurd," he said. He said the cameras had done no more than eye witnesses.

He said that the facts of this case, even taken at their highest, fell far short of engaging the constitutional right to privacy, never mind excluding evidence.

"If it should turn out that the CCTV implicates Mr Thompson, he is not entitled to call in aid the provisions he invokes to cover his tracks," he said.

He added that, if acquitted, he could pursue any alleged breaches of his privacy rights through other channels.

"We reject the notion that any or all of the CCTV evidence should be ruled inadmissible," he concluded.

The trial continues before Justice Hunt, presiding, with Judge Flannan Brennan and Judge Gerard Griffin.

The court heard previously from dozens of property owners and managers, whose private CCTV footage was used in the investigation.

Mr O'Higgins cross-examined many of them on whether their systems were registered with the Data Protection Commissioner and whether they had signs in place warning that CCTV was in operation. They had either not registered their systems or were unaware of an obligation to do so. Most also had no warning signs erected.

Mr O'Higgins addressed the three judges yesterday on why he said the footage should not be admitted into evidence.

"The law is not being complied with and the guards are getting the benefit of illegally created evidence," he said.

"I'm asking the court to make the following adjudication: that the evidence was all illegally created, that the guards are aware of this and the effect of making the recordings is in breach of my client's rights, if the prosecution prove it was him."

He said that the occurrence of the "unlawfully generated footage" was endemic.

"The guards are aware and are drawing from a well that is contaminated," he suggested. "The well includes a breach of the citizen's right to privacy."

He acknowledged that this was not an absolute right. However, he said that the legislature had struck a balance, but that the law was not being enforced.

Sean Gillane SC, prosecuting, said in reply that there was not an authority in the western world supporting what Mr O'Higgins was asking the court to do.

"It is also an argument without any authority, and there's good reason for that in circumstances where we've been living with ubiquitous CCTV systems for decades," he said.

He said that here could be no reasonable expectation of privacy in the circumstances.

Replying to the defence's citing of the Digital Rights Case, he said that it was concerned about storing information about people.

"Here they weren't storing it. They were deleting it," he said of the private CCTV owners. "It disappears unless the guards go get it and the Supreme Court is repeatedly telling them they must go get it."

He said that, according to the defence's argument, crime should no longer be committed behind closed doors.

"Stand under the camera and do it there because the EU says privacy rights have been breached," he said, pointing to what he described as an illogical argument.

"The system would fall into disrepute," he added.

"No piece of legislation should be given an absurd interpretation unless unavoidable," he said, quoting from a previous judgment.

He said that there could be no expectation of privacy when passing somewhere such as a petrol station.

"There is no privacy in the commission of a crime," he submitted.