Harald Gloeckl, a former employee of Germany's second-biggest public-sector Landesbank, said Ecclestone was told in several meetings in 2005 that BayernLB might consider replacing him because it "could do without him."
Former BayernLB banker Gerhard Gribkowsky is charged with selling Formula One rights in return for a bribe, with the involvement of Ecclestone.
Gribkowsky is charged with his deal costing the bank 66 million euros and him pocketing about 32 million euros as part of a bribe. The trial follows his arrest in January and is expected to last several months.
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Gloeckl said on Wednesday he was unaware of any payments made to Gribkowsky at the time and only heard about their alleged existence from prosecutors years later.
Towards the end of BayernLB's involvement with Formula One, Gribkowsky attended more and more Formula One-related meetings without the rest of his team because "that's the way Bernie wants it," Gloeckl said.
Gribkowsky repeatedly said internally that he might dismiss Ecclestone, but at the same time he boasted about his tight relationship with the 80-year-old Briton and toyed with the thought of succeeding him.
Gribkowsky told his colleagues at the bank that Ecclestone had once, before the alleged bribery payments took place, brought him a briefcase filled with $20 million, the witness said. Gloeckl added he did not know any details of the incident.
Ecclestone, who effectively runs Formula One, is expected to be the key witness in the trial in early November. He has denied any involvement and has said he did not bribe the banker.
BayernLB had a stake in Formula One up to 2006 along with JP Morgan, Lehman Brothers and Ecclestone's family trust.
The banks had acquired a 75 percent stake in F1 holding company SLEC after the collapse of Germany's Kirch media group, which had borrowed some $1.6 billion (1 billion pounds) from them. BayernLB was Kirch's biggest creditor.
SLEC was sold to the current Formula One rights holders, private equity firm CVC, in 2006 with Ecclestone remaining hands-on in running the business.
