According to Crown prosecutors, the tonne of Class A and B drugs - with a combined street value of more than €45 million - was imported through a route into Dover which was busted in 2017 when Britain's National Crime Agency (NCA) and the Garda's Drugs and Organised Crime Bureau moved in and took him down.
Bomber, who is regarded as Daniel Kinahan's UK business partner and who sat at the very top of the Byrne Organised Crime gang for two decades, is the biggest scalp so far in the fight against the Kinahan mafia.
The 53-year-old Dubliner appeared in court in Ipswich, south-east England, for a hearing relating to sentencing on Friday and told Justice Martyn Levett that it had taken him three hours to get there from prison, where he remains in custody.
His co-accused, Gary Vickery (38) and Daniel Canning (42), attended the hearing remotely as both are on bail - the pair were told that they need to surrender to the UK authorities by July 16 or face becoming fugitives.
Details of the prosecution case against Kavanagh, Vickery and Canning emerged as Judge Levett was told that negotiations with the defendants are ongoing as they attempt to strike a plea deal in relation to the amount of drugs involved.
All three have pleaded guilty to conspiring to import the drugs into the UK and to money laundering, while Canning has pleaded to a further firearms and ammunition charge.
However, all three want the Crown to reduce their case regarding the levels of drugs imported.
Riel Karmy Jones, QC, told Judge Levett that the court had not received any documents from Kavanagh or Canning in relation to their position and said that the Crown was looking for all parties to agree on a starting position of 20 years in relation to the cocaine trafficking.
Ms Karmy Jones said that the judge could consider the cannabis as an aggravating feature of the overall sentence or it could be used for a small consecutive sentence, but she repeated that there was no agreement as yet between the parties.
She also told the judge that the defence were anxious to hear if the judge would be in agreement with the position of a 20-year starting point before any deal was struck, but Judge Levett refused to be drawn on what he planned to do.
He said he was not in a position to give any indication regarding what he would do about sentencing, but warned that the longer talks between both parties went on and the sentencing moves towards a 'Newton Hearing' the less credit the three will get for their guilty pleas.
Justice Levett also said there were many considerations regarding mitigating and aggravating circumstances which would reduce or increase any sentence length and also whether sentences for the different offences would run concurrently or consecutively.
The Newton Hearing will be heard in August if it goes ahead and will thrash out the issues over two weeks before the judge.
Judge Levett addressed the unusual circumstances surrounding the fact that Vickery and Canning remain on bail despite their guilty pleas and said it was not clear if they would have to pay for their own hotel quarantine if they needed it on arrival in the UK before they went to prison.
He said he would issue a warrant for their arrest and proceed to a European Arrest Warrant if needed, which would result in an extra year on top of their sentences. However, he said it was preferable if they would surrender themselves and avoid that scenario.
Both are to hand themselves in to UK authorities on July 16, at which point it will be decided whether agreement has been reached or the Newton Hearing will go ahead.
While Kavanagh could not be seen on the courts camera system, he was present and the judge addressed him at the end of the hearing to tell him he would have to return another day.
"How long did it take you to get here?" he asked. A man speaking in a Dublin accent replied; "Three hours."
The sentencing of Kavanagh and his cohorts has been one of the most drawn-out in any court. All three pleaded guilty in July 2020 to the charges and were first due for sentence last October, when it emerged that there was legal wrangling going on in the background in relation to matters before the courts.
On Friday, when the massive amounts of drugs at the centre of the proceedings emerged, it was clear that the criminal is facing an enormous sentence. In the UK a judge can hand out a sentence up to life for drug trafficking.
Kavanagh's former partner James Mulvey was handed a 32-year prison term for conspiracy to import more than €100 million worth of cocaine. He was arrested in Lithuania in 2017 after years on the run.