Anas Altikriti

The family has also received similar letters about account closures for their business accounts.

Anas Altikriti, an outspoken pro-Palestinian commentator, told BuzzFeed that each member of his family (himself, his wife and his two children, one 12 and another 16) received an identical letter on the same day stating that their bank accounts would be closed.

The letter said: "After a review of your relationship with HSBC, we have taken the decision that we no longer wish to provide you banking facilities and are closing your accounts."

It also asked the four individuals "not to approach them regarding any kind of explanation because they are not going to give us any and not to approach them or apply to re-open any accounts with either them or any of their affiliated," according to Altikriti.

A spokesperson for the bank told BuzzFeed that race or religion does not pay any part in any decision to close down any customers' account.

"We do not discuss individual customers, nor do we confirm whether an individual or business is, or has been a customer," the bank said in a statement.

The statement also noted that, following a $1.9 billion fine from US and UK governments, the bank launched "a programme of strategic assessments to all of its businesses", which resulted in the bank ending relationships with customers in more than 70 countries.

"Discrimination against customers on grounds of race or religion is immoral, unacceptable and illegal, and HSBC has comprehensive rules and policies in place to ensure race or religion are never factors in banking decisions," the statement added.