If you both purchase a property and are jointly named on the deeds the income received will be split equally between you. This basis applies regardless of who actually paid for the property. However if you wish the rents received to be apportioned in unequal shares, for example, giving a greater share of the income to one spouse than the other you will need to get a solicitor involved in order to make the claim valid.

Alternatively if you purchased the property in unequal shares at the outset you can ask HMRC to tax the income in the same proportion as your actual legal ownership. Note, you must have agreement in place from HMRC before you do this, in the interim the income must be split on a 50:50 basis.