A man has been charged with criminal damage and threatening behaviour after an alleged incident outside showman David Blaine's box.
Blaine is a quarter of the way through his 44-day stunt
Stephen Charles Field, 38, was arrested early on Tuesday and taken to a south London police station.
The cleaner, from Godalming in Surrey, is alleged to have climbed a scaffold support tower connected to Blaine's cage and to have tried to cut the line which delivers water to the American illusionist.
He was released on bail and is due to appear before Tower Bridge Magistrates' Court on 30 September.
Blaine is taking part in an endurance test, staying 30 feet (nine metres) off the ground in his plastic box, with only water, for 44 days.
Blaine, 30, who has taken part in similar feats in the US in the past, is 11 days into the London stunt.
He has been taunted by people hitting golf balls at his box, a female spectator partially stripped off beneath him and he has been woken by drumming.
Laser pens have been shone at him - which reportedly caused concern because he thought they may have been from rifle sights.
Tormentors have also thrown eggs and bananas and even sent a burger up on a remote-controlled helicopter.
At the nine-day stage, using a microphone in his box, he said: "I like watching people eat, actually" - but said he was thinking about food a lot.
"When you go without eating for nine days... I start thinking about the most specific things that I eat... everything that I've ever eaten that I ever liked," he said.
"I close my eyes and see those vivid images, it's just like I'm really eating it. I mean, detail by detail, you see it too... and this is only nine days."
He also said the feat was "getting tough" and said: "I wonder how much longer 'til my mind goes away.
"Not permanently - but before I go a little crazy. I'm starting to laugh a lot - obsess about really weird details and stuff."
Some local residents have complained about traffic coming to a standstill on Tower Bridge as motorists slow down to look at the stunt.
Blaine's endurance challenge - dismissed by some critics as an illusion - is being televised by Sky One and Channel 4.