An Israeli theatre company performing a Hebrew production of The Merchant of Venice - Shakespeare's troublesome play about anti-Semitism - arrived at London's Globe Theatre amid calls for and against a boycott. Cue action on and off stage.

A festival consisting of all 37 of Shakespeare's plays performed in a short space of time is likely to induce some confusion into the mind of even the bard's most ardent fan. Richards can become muddled with Henrys, shipwreck locations misplaced.

Confusion can lead to doubt when - as is the case in the current Globe-to-Globe season - each play is being presented by a different company from a different country in a different language. That said; there are some features so particular to certain plays that they are unmistakable.

For instance, there's that one featuring a balcony scene, rival gangs, heartfelt passions and some argy bargy. At least there was one - Romeo and Juliet - but as of Monday night, there is now another.

I was at the Globe Theatre on Monday to see the Habima Theatre Company of Tel Aviv present its take on The Merchant of Venice, which it turned out contained a balcony scene, rival gangs, heartfelt passions and some argy bargy. Some of these elements were performed on stage by the players - Shylock was subjected to a kicking - but much of the action took place in the auditorium by way of a protest within the play.

The production itself had become a stage on which people opposed to Jewish settlements in the occupied West Bank chose to express their feelings. For Habima's two-day run, the Globe took the precaution of providing a highly attentive, specialist audience for any would-be protesters, in the muscular shape of several polo-shirted security personnel.

These men of action were dotted throughout the theatre, each with a piece of coiled plastic snaking like ivy up their shaved necks before disappearing behind an exposed ear. Their bodies were as still as their heads were animated, which were twitching as if following a fly. They were waiting for the action to start: for these particular spectators all the auditorium was a stage.

Five or so minutes into the opening scene, the protesters' show got under way with aforementioned balcony scene. A middle-aged woman quietly unfurled a banner that read "Israel Apartheid Leave the Stage". Behind her a thin man in a blue linen suit started to wave a Palestinian flag.

The security guards were well rehearsed and recognised their cue. Chins went forward, chests came out, and Popeye-like forearms divined a path through the seated spectators. Thirty seconds later both the banners and their owners had gone. The strong men returned to their positions and awaited the next act.

It came a few minutes later in a reprisal of the balcony scene, this time with a different cast but the same resulted: swift eviction.

As the polo shirts left the area three well-dressed 50-something men, who wouldn't look out of place at a book festival, stood up towards the back of the balcony and placed white sticky labels over their mouths. This caused some confusion among the security fraternity. What to do? A network of nods from the foot of the stage up to the balcony revealed that the audience was not made up entirely of theatre lovers. Several men - some in suits, others more casually dressed - had blown their cover.

Before a decision could be made about how to handle the three self-stickered gents, the situation was complicated by a handsome grey-haired woman at the front of the balcony rising to her feet and applying a white patch to her mouth. More head scratching and finger pointing ensued.

Meanwhile, Habima's actors continued to present The Merchant of Venice in Hebrew to a distracted but generally appreciative audience. Their show was going on.

And so was that of the protesters. Half an hour later and the three men and single lady were still standing. The gesturing from the ground had all but stopped from the security team but tension was in the air, a sense perhaps that there would be a main event to follow the balcony cameos.

It never materialised. There was some shouting and a bit more banner waving, but the protesters had made their point and so had the men from security. Both parties over-acted at times, most notably when a six-foot security man made of pure muscle accused a woman who looked to be in her 60s of assaulting him, when all she had done was touch his arm.

She too found herself being escorted out.

There is much to ponder about what happened during this play. Plenty has already been written and spoken about the perceived rights or wrongs of this production taking place - such as this actor Mark Rylance joining the call for a boycott and author Howard Jacobson describing the boycott as "McCarthyism" - and there is likely to be some more about the rights or wrongs of staging a protest in a theatre where the majority of the people have paid to see a show that has received some warm reviews.

The thought that crossed my mind, as I watched events unfold on the stage and in the auditorium, was not so much how resonant the themes contained within Shakespeare's play still are, but what protests, if any, would The Merchant of Venice have provoked had it been written today and not more than 400 years ago?