Bloxsome, nicknamed for his tendency to only insist on the best case scenario, accompanied the prince as he was driven from his Royal Lodge property in Windsor Great Park to meet his 95-year-old mother at Windsor Castle.
It has been suggested that Andrew brought ‘Good news Gary’ to the crunch talks in recognition of the seriousness of the unprecedented royal clash.
Other speculation has Mr Bloxsome there in an attempt to help Andrew explain to Her Majesty the machinations of his New York sex case.
However, it is understood that he was ultimately denied entry to the castle and instead had to wait outside in the car park during the 90-minute meeting.
He is now believed to be the prince’s closest adviser after his former private secretary Amanda Thirsk agreed to quit in 2020 when Andrew was forced to step back from royal duties over his relationship with Jeffrey Epstein.
Mr Bloxsome is thought to have been appointed by Andrew in January 2020 to help with the potential legal fallout from his friendship with Epstein
He has previously represented footballers facing charges over nightclub brawls and in 2019 defended former Tory party treasurer Simon Day when he was acquitted of election fraud.
The prince is also being advised by Clare Montgomery QC, who battled to save Chilean dictator Augusto Pinochet from extradition after he was accused of human rights abuses.
Other clients have included Shrien Dewani, who was charged with murdering his wife in South Africa in 2010 and was later acquitted.
Last year, she represented a former paratrooper accused of murdering an IRA commander in Belfast in 1972. The veteran, known as Soldier A, walked free when the trial collapsed.
Meanwhile, there have been calls for Prince Andrew to be stripped of his Duke of York title, as legal developments in the United States appear to turn against the Royal.
Asenior member of City of York Council has begun a campaign to stop Andrew using the title after the Queen removed his honorary military roles and he gave up his use of the HRH style in the wake of the sex abuse case being taken against him.
It comes after US judge Lewis Kaplan refused to dismiss the case after hearing arguments from Andrew and his accuser Ms Virginia Giuffre.
The prince has also had all of his military titles and royal patronages taken away as a result of the controversy.
Darryl Smalley, Liberal Democrat executive member for culture, leisure and communities at the council, said: “York’s unique connection to the crown and the monarch is an important part of our city’s legacy, history and a great source of pride.
“No-one is above the law and all allegations should rightly be fully investigated, particularly following the recent distressing court cases.
“We stand with all victims, whose harrowing stories have shocked us all in recent months.
“Whilst Prince Andrew remains innocent until proven guilty, Buckingham Palace and the Government must consider the implications of these troubling allegations moving forward.
“Having been stripped of his military roles and royal patronages by the Queen, he should also now relinquish his title as Duke of York.”
Labour MP for York Central Rachael Maskell agreed, tweeting: “It’s untenable for the Duke of York to cling onto his title another day longer; this association with York must end.
“There’s a very serious allegation made against this man of privilege & entitlement.
“I’m working with agencies to tackle sexual violence & misogyny. #NotinYorksName”