Union bosses at RMT have written an open letter to train operators Southern, Southeastern and Thameslink, along with Network Rail, claiming rail staff are being abused by angry commuters over the travel chaos.
The union claims that staff have been threatened, had hot coffee thrown over them and been spat at by passengers who “take out their anger on the station workforce”.
It also claims staff warned bosses about problems with the plans, but were ignored.
The works, which began around Christmas, have caused commuter misery as trains are delayed and cancelled on a routine basis.
This whole affair and its catalogue of failures has placed my station staff in the firing line of verbal abuse and physical assaults from customers. I must advise you that it is totally unacceptable that my members have hot coffee thrown over them or are spat upon by irate out of control passengers.
The letter calls for “preventative measures”, including more staff, more management and – where necessary – police support - to be put in place “without delay”.
RMT general secretary Mick Cash said: “Our members at London Bridge are furious that they are taking the full force of the anger of passengers while those responsible are tucked up snug and warm in their offices. It is disgusting that staff charged with crowd control are being threatened, spat on and assaulted with hot coffee.
“We want measures put in place immediately to protect our members from this threatening and abusive behaviour.
“RMT is also angry that concerns voiced by staff who foresaw the problems at the station were ignored. There was a woeful lack of meaningful consultation and we are paying a heavy price for that now. That is a reflection of the fragmentation unleashed on our railways by privatisation.
“All it would take in the crushing we saw last week is for one person to lose their footing and the threat to life and limb is only too obvious. RMT is demanding action, not excuses and the usual pathetic buck-passing by the myriad of companies and contractors involved.”
But a joint spokesman for Network Rail and Southern said there had been no reports of any assaults taking place after the most recent rush hour chaos last Tuesday evening, when crowding became so intense that commuters were crushed and some forced to crawl under or climb over barriers to escape.
"However, assault on our staff, whether verbal or physical is taken very seriously and it is not tolerated under any circumstances," he said. "Reports of staff abuse are acted upon immediately with the instigation of chain of care procedures and British Transport Police involvement."
The spokesman added: “We appreciate that these have been challenging times for our staff and they have performed extremely well under challenging circumstances. With the support of the Southern and Network Rail management teams, they have coped admirably with the high numbers of passengers entering the station recently during disruption.
“Network Rail and Southern are working to improve communication at the station and how we deal with disruption at one of the country’s busiest stations."