Millions of commuters face nightmare journeys as 6,500 Tube workers threaten to strike late this summer.
The Rail, Maritime and Transport (RMT) workers' union said there was a "massive gulf" between them and Tube bosses in talks over pay rises.
The "blatantly unfair" dismissal of a Tube driver and claims of harassment at Canary Wharf station added to the row, the union said.
It has now threatened to ballot 6,500 Tube workers, including train and station staff, plus about half of London's drivers, for strike action if there is no "acceptable pay offer" by August 23.
If the strikes went ahead, it would "bring the whole network to a standstill", an RMT spokesman said.
But Geoff Pope, chair of the London Assembly's transport committee, said: "Once again it is outrageous that Londoners should suffer delays and inconvenience from the total inability of London Underground (LU) and its staff to work together.
"Commuters have enough to deal with and should not be constantly drawn into these disagreements."
The union said it wanted a short-team pay rise package, but LU offered a four-year deal on the condition that staff work half an hour later when necessary.
LU replied that it has since made an "improved" offer, and was awaiting feedback.
'Strike should not be first step'
In a separate dispute, more than 100 drivers on the Jubilee line will be balloted for strike action after one of their colleagues was sacked for passing a red light.
Driver Raj Nathvani has eight and a half years experience with no safety breaches, but was fired after he overran the danger signal.
"He reported it to his controller and proceeded at caution. Ahead of him were green signals and no points, but he was sacked without mercy because he didn't follow procedure exactly," RMT general secretary Bob Crow said.
The union also accused LU of victimising Mr Nathvani's RMT representative, Les Bruty, who faces disciplinary action and possible dismissal for a "minor incident" whilst driving an empty train.
But an LU spokesman insisted: "Passengers expect nothing less than that safety should be our prime concern and we cannot tolerate breaches of safety rules."
About 80 station staff at Canary Wharf will also be balloted over claims that managers harassed a female worker after she was sexually assaulted there, while a gay worker allegedly received homophobic insults.
Tube bosses takes harassment "extremely seriously" and have already investigated the claims, an LU spokesman responded. "If there are further issues then balloting for strike action as a first step is not the way to resolve any issue."
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