Readers’ forum: Can I continue acting for my client?

I act for a private company which has two (unrelated and not otherwise connected) shareholders who each own 50% of the share capital. I don’t act for the shareholders individually. The company is profitable and the shareholder/directors extract large dividends each year.

One of the shareholders came to see me last week and said that there had been a big falling out between the two of them. He also told me that he believes that the other shareholder has not been declaring the dividends he received from the company on his tax return. He can’t prove this but has heard him boasting about ‘beating the tax man’. What are my professional obligations here given: a) I don’t act for either director; and b) this is only an allegation? Do I have to make an anti-money laundering report or cease acting for the company? It has been a good...