Hawkins\Brown took a 39 per cent blow to its operating profit during its last financial year, according to accounts filed at Companies House
Turnover at the practice dipped by 11 per cent from £30.6 million to £27.4 million, in the year to 31 March 2019.
But the operating margin slipped from 23 per cent to 16 per cent year-on-year, as operating profit tumbled from £7.3 million to £4.4 million.
Hawkins\Brown declined to comment on its results or say why its margin was squeezed.
The average number of staff at the architect also fell from the previous year, from 262 to 250. The average number of technical staff employed by practice fell from 233 to 218.
In May, two months after the end of the reporting period, the firm made 19 staff redundant.
However, the company has since won six jobs with a combined value of more than £650,000 on the Design and Urbanism Panel run by Transport for London and the Greater London Authority.
The practice entered the top 10 of the AJ100 rankings of the UK’s largest firms for the first time in its 30-year history in 2018.