Should voluntary disclosure be the way forward for wife not declaring rental income?

Question A husband and wife have been letting out a house for 5 years, but not declaring the income. I have received a letter from HMRC asking about the rental income, but wife hasn't. As husband is higher rate taxpayer, they wanted the wife to receive most of the rental income. I don't think they can do this as the property is owned by both of them, and no form 17 has been been submitted. Am I correct? Also, as wife hasn't been contacted by HMRC, is it worth making a voluntary disclosure? Or is that a waste of time as she's only making the disclosure because husband has been contacted by HMRC and therefore the disclosure could be viewed as prompted?
 
Arthur Weller replies:
If the house is in joint names, and no Form 17 has been submitted, the rental income is attributed 50:50 to husband and wife, automatically. It is still worth making a voluntary disclosure to HMRC now for the wife, even though the husband has already been contacted by HMRC.