Schmidlin Group's facade division, one of the companies that worked on Norman Foster's Swiss Re building's memorable external appearance, is in administration.
The company is known in Britain as one of the most prestigious cladding companies, providing kit for such schemes as Richard Rogers' Heathrow Terminal Five.
The number of other major schemes currently under way in the UK that will be affected is unknown - but there is no doubt it will be large.
The firm is in deep financial trouble. Company bosses have admitted that they discovered a 13 million swiss franc (£6 million) hole in its books when they introduced a new accounting system last year.
They also said that competition in the European facade market had become increasingly competitive.
However, in the statement, the firm insisted that the Schmidlin Group, the parent company, was unaffected.