An activist who was involved in attempts to secure the release of a British hostage in Iraq has spoken of his anger after he was told that his bank account is to be closed by HSBC.

Anas Altikriti, chief executive of the think tank the Cordoba Foundation, said he had met with a "wall of silence" from HSBC over its decision to close his account and those of his wife and two sons aged 16 and 12 years old.

The Cordoba Foundation, along with Finsbury Park Mosque in north London and the Ummah Welfare Trust (UWT) have also been told their accounts are to be closed by the bank.

Mr Altikriti, 45, who was born in Baghdad and came to Britain as a young child, said he opened an account with the Midland Bank - now part of HSBC - as a teenager with just a £10 note nearly 30 years ago.

He flew to Baghdad in late 2005 in a personal capacity in an attempt to secure the release of British peace campaigner Norman Kember, who was being held hostage in the country. Mr Kember, along with two Canadians held hostage, were eventually released in 2006 after 117 days in captivity as the result of a British-led military operation.

Mr Altikriti, from London, said he was angered by the failure of the bank to give an explanation for its action.

"I am angered because of the wall of silence and the tone of the letter. It is difficult to take as I regard myself as a law abiding citizen who tries to make things better in conflicts around the world and tries to promote peace and dialogue," he said.

"When you are left with no explanation, you are left to speculate, from the whole context of the other organisations that have been targeted, I would speculate that it is because of my activism either for Gaza or for the Palestinians. I have also been vocal in my attacks on the governments of Saudi Arabia and United Arab Emirates regarding their stand on the military coup in Egypt."

Finsbury Park Mosque, where radical cleric Abu Hamza was once a prominent figure, described the move by HSBC as "astonishing".

Mosque chairman Mohammed Kozbar told the BBC: "The bank didn't even contact us beforehand. Didn't give us a chance even to address (their) concerns.

"For us it is astonishing - we are a charity operating in the UK, all our operations are here in the UK and we don't transfer any money out of the UK. All our operations are funded from funds within the UK."

Meanwhile, the Ummah Welfare Trust (UWT) was told its account will be closed after two months in a letter from the bank dated July 22, in which HSBC said: "Provision of banking services to Ummah Welfare Trust now falls outside of our risk appetite."

Registered with the Charity Commission as the Amanat Charity Trust, UWT provides emergency relief such as food and medical supplies to conflict zones, including Syria and Gaza.

It is not the first time it has had its bank accounts shut down - Barclays did the same during the conflict in Gaza in 2008.

A statement on the Bolton-based charity's website said: "As the attacks intensify in Gaza and innocent people continue to be killed, HSBC Bank has issued a two-month notice to Ummah Welfare Trust to close down its accounts.

"This is similar to what Barclays did to Ummah Welfare Trust during the previous Gaza war in 2008. A notice then was also served for the charity to close its accounts.

"Ummah Welfare Trust reassures supporters that, in response, the charity will increase its support to the orphans, widows and injured civilians in Gaza through its other bank accounts."

Trustee Shaykh Muhammad Ahmad, in a video statement on the site, also called on its supporters to join in a "campaign to boycott HSBC".

An HSBC spokesman said: "We do not discuss relationships we may or may not have with a customer, nor confirm whether an individual or business is, or has been a customer. In general terms, decisions to end a customer relationship are not taken lightly, but are absolutely not based on the race or religion of a customer.

"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 the decisions we make."