In a statement, the firm said: "Arup can confirm that as a result of a downturn in some parts of its London operations, 43 jobs have been lost, out of total of some 2000. This follows an extensive consultation with staff working in London. Everything possible is being done to assist the people affected."
It is understood that the majority of the cuts will be in the building engineering group, and that Arup's international offices will not be affected.
The redundancies were announced despite the fact that Arup has recently won several high-profile projects, including its appointment to draw up a cost plan for the London bid for the 2012 Olympics.
The Arup cuts follow job losses at consultant Citex earlier this month, which were in response to a downturn of work in the South-east. Leading commercial architects such as Gensler were forced to make job cuts late last year in response to the downturn caused by the 11 September attacks on the USA.