Hi
Thank you for your question, please refer to guidance -
PIM1030 - Introduction: jointly owned property & partnerships - Jointly owned property: no partnership, which states ‘However, where the joint owners are husband and wife, or civil partners, profits and losses are treated as arising to them in equal shares unless:
both entitlement to the income and the property are in unequal shares, and
both spouses, or civil partners, must inform HMRC that their share of profits and losses is to match the share each holds in the property.’
You can inform HMRC of unequal shares by completing a Form 17 available at
Declare beneficial interests in joint property and income
Thank you