AEG and Azoff-MSG are butting heads over an edict issued by AEG informing agents and promoters that acts who opt to play at MSG’s Forum instead of AEG’s Staples Center will be blocked from performing at the AEG-operated O2 Arena. At 20k-capacity, the O2 is the lone indoor venue of its size in London, making it the only game in town. Wembley Arena, the second biggest venue at 12.5k, is also operated by AEG.

The move was reportedly made in response to MSG’s alleged refusal to book acts into Madison Square Garden if they played at Staples instead of the Forum. Variety broke the story on Friday (6/30), just as the biz was shutting down for the Fourth of July four-day weekend, and one day before the ban was scheduled to go into effect.

In recent months, the ongoing tensions between AEG and MSG have resulted in several big acts who’d previously headlined the Garden choosing instead to play at Forest Hills Stadium, a 16k-capacity shed that AEG has been operating exclusively since April, in a situation paralleling the Staples-Forum standoff.

Live Nation, the biggest player in the live-music space, wasted no time putting its two cents in, according to Variety, criticizing AEG’s pressure tactics as anticompetitive and in violation of antitrust laws given the absence of a competitive arena in London. LN then doubled down, reportedly threatening withhold shows from AEG venues worldwide. As a result, an AEG took a shot at LN as well as MSG in a statement provided to Variety, turning the dustup into a three-way fray.

This latest skirmish in the fierce ongoing rivalry among the big three concert powers prompted this response from a top agent at one of the two big agencies: “[AEG] dropped all this on the Friday before the holiday, probably because they were embarrassed. AEG should be embarrassed at their anti-artist stance, and it feels like Denver and Phil [Anschutz, AEG’s owner] insisted on doing it, and Jay [Marciano, AEG’s CEO] and the boys waiting till late Friday before a holiday to bury the coverage. Interestingly, neither MSG nor Live Nation cared enough to even comment.”

All in all, this brouhaha has become a colorful, combustible subplot to the summer touring season.