Also out Tuesday was a survey from professional services firm Deloitte which showed new building activity in the central London office market screeching to a sharp slowdown in the six months to the end of the third quarter.
The data revealed a 42 percent tumble in new activity with 2.8 million square feet of new office developments across 40 schemes being added to the pipeline to the end of September versus 4.8 million square feet across 51 projects added in the previous six-month period.
The picture on the letting side points to the resilience of new-builds,with nearly 50 percent of recently completed space already let. However,turning to existing space, the picture is far weaker with volume leased in the first nine months of 2016 a significant 37 percent down on last year.
The poor leasing figures combined with a jump in space coming online has pushed central London office vacancy rates from near record lows of around 3.9 percent at the end of 2015 to 4.8 percent by the end of September. "Subdued" appetite from financial services firms has driven the spike, says Deloitte.
While prime rents have held up to date, should the softness continue, they could be the next shoe to drop.
Land Securities' Noel advised watching timetables, observing, "It'll be very interesting to see how many development intentions get moved out."
Chris Lewis, head of occupier advisory at Deloitte Real Estate told CNBC via email that it was time for developers to proactively address a changing market.
According to Lewis, "There is a very real challenge looming for developers caused by a changing occupier demand pattern resulting from challenges faced not only through political and economic change but also operational disruption relating to aspects like millennials, technology and automation."
"The best way for this to be addressed in building terms is to create the most flexible space possible allowing for choice around specification, layout and quantum," he recommended.