The son of a billionaire art dealer could face jail after he admitted banging his girlfriend’s head against a wall during a drunken row at his multi-million-pound Knightsbridge apartment.

Joseph Nahmad, 31, carried out a “considerable beating” on partner Georgia Barry at his home in March and had attacked her in another incident five months earlier. He pleaded guilty to two charges of assault occasioning actual bodily harm.

Southwark crown court heard Nahmad first attacked Ms Barry on October 27 last year and again on March 8 this year at his apartment in The Knightsbridge complex.

Prosecutor John Fairhead said Ms Barry had also accused Nahmad of picking up a knife during the second incident, but he denies this allegation.

“This is in the context of a considerable beating — banging her head against a wall,” he said. “Both parties drank to excess and she on two occasions says she was tipsy.”

Nahmad pleaded not guilty to a third alleged attack at celebrity nightclub Tape London, in Mayfair, and the charge was dropped by the prosecution.

Defence barrister William Clegg QC told Monday’s hearing: “There was an incident in a nightclub where a scratch and bruise were sustained. Very minor injuries.”

He added that Ms Barry had attempted to withdraw all three allegations against Nahmad, who told the court: “She was in a consensual, loving relationship that at times became toxic.” Nahmad is the son of billionaire David Nahmad, who with brothers Giuseppe and Ezra established the family as world-famous fine art dealers.

Following in the footsteps of his father, uncles and cousin, also called Joseph, who runs the Nahmad Contemporary gallery in New York, Nahmad made his own waves in the art industry in 2016 with the launch of Nahmad Projects, in Cork Street, Mayfair. At the time of the launch, the young art dealer promised to “bring a radical edge to Mayfair’s contemporary art scene”.

Judge Jeffrey Pegden QC bailed Nahmad until September 2 when he is due to be sentenced and could face a custodial term.