Readers’ forum: Tax consequences of unexpected rent entitlement

My client has a part share in land. His co-owner rented it out for a small sum to cover expenses and my client said he had no interest in receiving a peppercorn balance. I was unaware of this arrangement but if there was an underdeclaration of an entitlement to rental income it would be trivial.

He is now getting divorced and has discovered that the co-owner relet the land at a significantly higher rental three years ago and did not tell him.

There is now a possibility that he will have to make a claim against the co-owner for three years’ share of £9 000 a year because his wife is claiming her share of it from him.

Could readers assist on whether he should make a disclosure of the entitlement while he argues about it? Is he liable for income tax on the rent...