When to declare and pay tax on interest only

My husband is currently a full time parent and has had no income from work for a few years. He does claim the full child benefit allowance. How much interest on savings can he earn before a) he is taxed and b) before he needs to complete a self assessment? I note the starting savings allowance but cannot work out at what point he would need to declare the interest… is it over £1000 personal savings allowance or over £5000 starting savings rate? Thank you

Hi ,

Please refer to guidance at : Tax on savings interest   . Thank you .