Green, also a former government minister, was chief executive and chairman of HSBC while its Swiss private banking arm helped wealthy clients evade tax.
Now, more than a month after the scandal broke, Green has for the first time addressed the issue after giving a lecture on the subject of belief in the City at St Michael's Cornhill church in the City.
Confronted by a Channel 4 news reporter, Green said what happened "was dismaying and a source of deep regret unquestionably."
I share with my colleagues who appeared before the select committee the dismay and the regret about what happened.
We worked hard at setting high standards I personally have always worked hard at seeking to follow high standards in my career and so what happened was dismaying and a source of deep regret unquestionably.
I am proud of working for HSBC I think it's a great company and I think it provides a great service to people around the world.
Did we get everything right? Maybe not. Did we work hard at trying to do the right thing? Yes we did.
And I'm also proud of how the present leadership team is taking it forward and learning from experiences.
When asked whether he knew about the files of data which revealed the scandal at the bank, he said he did not know about it.