We reported earlier this week that 12 property developers had coughed up the cash to sponsor the attendance of council leader Peter John and two council officers at the MIPIM property trade fair to be held in March in the French town of Cannes.
Now the show has been postponed until early June due to growing public health concerns about the coronavirus.
"The well-being of our clients and staff is our priority," said Reed MIDEM chief executive Paul Zilk.
"Given the evolving context, the best course of action is to postpone MIPIM to June.
"This is not a decision we have taken lightly. We believe these new dates will provide the international MIPIM community with the opportunity to achieve their business objectives.
"We are grateful to our clients for their support and constructive input during this challenging period, and we look forward to talking with them in the coming days about MIPIM in June."
The rescheduled summer MIPIM will come too late for Southwark's Cllr Peter John to attend – he announced this week that he is stepping down as council leader and chair of London Councils on 25 March.
Lambeth Council was also due to send at least two officers – chief executive Andrew Travers and Sara Waller, co-strategic director of sustainable growth and opportunity – to MIPIM.