My husband is a British passport holder and he has withhold my passport and I can't return to UK. Which visa category should I apply for?

The client is facing an issue regarding her return to the UK for an exam in London. She possesses a spouse visa, and her husband, who is a British passport holder, is currently withholding her Pakistani passport. The client is presently in Pakistan while her husband remains in the UK. Her Pakistani passport was issued on 15 April 2024 and is valid until 15 April 2034. She is seeking guidance on how to apply for the appropriate visa category to return to the UK to attend her exam in May.