HSBC's decision to close bank accounts belonging to a number of British-based Muslim groups and their leading figures has caused anger.
Among those affected are the Finsbury Park Mosque and the Ummah Welfare Trust, which raises funds for Palestinians in the West Bank and Gaza.
Anas Altikriti, founder of the Cordoba Foundation think tank and a leading Muslim activist in Britain, said HSBC had informed him, his wife and two sons, that their personal accounts would be closed. He said the bank had provided no explanation for its decision.
On Twitter Mr Altikriti, former head of the Muslim Association of Britain, which represents the Islamist Muslim Brotherhood in this country, added: "The only explanation that comes to mind is my work for #Palestine & #Gaza. If not, then I call on HSBC to deny it.
"If HSBC or whoever's behind this thought that it would deter me or my family, then they have miscalculated. Big time. #Gaza"
In a statement HSBC said the closures were not based on race or religion.