Revenue increased to £842.9 million in the six months to September, more than half of it earned outside the company’s original UK base, from £664.2 million in the same period last year.
But in the UK, operating profit declined to £24.6 million in the six months to September from £30.9 million in the same period a year earlier, and revenue from £454.7 million to £420.4 million.
UK staff numbers also declined, from 10,246 to 9,403. Planning's annual consultancy survey, which will be published tomorrow, shows that Atkins employs 40 chartered planners in the UK, a decrease of five on 2010.
Chief executive Uwe Krueger said: "The group has delivered solid half year results.
"Notwithstanding the continuing challenges we face, with our diversified exposure to a range of end markets and geographies and good work in hand as we move into the second half, our overall outlook for the year remains unchanged."
Atkins said its multi-disciplinary capabilities had offset the decline in business from the UK public sector.
But it saw "significant pricing pressure" in its highways and transportation business and said delays in letting signalling framework contracts’ had hit its rail business, though workload was improving in the water and environmental sector.
The company said that in the UK it had "a solid, diversified platform to help navigate short-term market challenges, and a breadth of expertise that will help us exploit opportunities when growth returns".