Hence on 11 December 1911 the London branch was inaugurated, just a few months after Credito Italiano opened its own branch on 18 September of the same year.
Following the inauguration, on 14 December 1911 the Regio Ministero del Tesoro (Italian Treasury) announced that it had chosen Banca Commerciale Italiana's office as its correspondent on the London market.
In order to expand its customer base, BCI asked its Italian branches to provide their City colleagues with names of British companies that were engaged in business with the bank's Italian corporate customers but not yet customers of the bank themselves.
In 1914 BCI opened a city agency in the West End; it would open a second one in Soho in 1920.
The London branch's activities became problematic during World War I, when the bank was forced to fire its German and Austrian employees; in 1915 its director, Siegfried Bieber, now considered an enemy subject, was himself forced to resign.
But the situation during World War II was even more difficult. Following Italy's declaration of war, the branch was shut down and liquidated in 1940, with its director, Carlo Lovioz, being expelled from Great Britain and shipped off to Portugal. The London branch would reopen only on 1 January 1971, created through the transformation of the representative office the bank had set up in 1947.

ASI-BCI, VCA; March 30, 1911; May 27, 1999; September 30, 1911; June 6, 1914; February 2, 1915; vol. 3, p. 48, 64, 69-71, 221, 254
ASI-BCI, VCA; February 27, 1919; July 2, 1920; vol. 5, p. 65, 312
ASI-BCI, VCA; July 2, 1920; February 26, 1921; vol. 6, p. 1, 92
ASI-BCI, VCA; November 16, 1937; vol. 18, p. 31
ASI-BCI, VCA; November 12, 1940; vol. 19, pp. 198-199
ASI-BCI, Signature Books