The firm said it had adopted a more stringent approach to risk management and was investing in computer systems to prevent a similar mistake recurring.
The firm, whose blue-chip clients include Allied Dunbar, UBS Warburg and Asda, is to abandon all offices apart from its City of London base, including its facilities management office in Bermondsey, south-east London, and its Sutton office, which carries out small construction works.
Miletrian said the closures would save £500,000.
In a written statement, chief executive Michael Dawes said: "The directors took the view that a period of consolidation was necessary for us to maximise our strengths and eradicate our weaknesses. Our main skills are in fit-out, refurbishment, facilities management and support services."
The directors took the view that a period of consolidation was necessary to maximise our strengths
Michael Dawes, chief executive, Miletrian
Dawes said the management team had been restructured after the departure of director Stuart McConnachie, who left in January.
The firm has promoted Paul Pullen and Andy Donoghue to construction and surveying directors and appointed Julian Munday marketing director. Dawes said: "We now have a better-balanced team to lead us into the future."
The group's turnover for the year to 31 March 2001 dropped for the second year in succession, falling to £39.6m. Pre-tax profit was £21,000 for the period, after being hit by £516,000 in restructuring costs and a £753,000 in provision for bad debts.
The family-owned group said its core London fit-out operation continued to be successful.