My wife is going to be applying for UK citizenship next month.

I realise that she should not be "related to" her 2 referees.

I'm fairly sure I know what this means, but I'd like to be certain. Does anyone know if there are any guidelines on who counts as a relative? eg. Do in-laws ?

Specifically, it would be great if my brother's wife could be a referee.

Thanks

As far as I'm aware, in-laws do count as relatives; the guidance says "not related to you," i.e. the applicant. If this meant blood relatives only then you could act as a referee for your wife!

Best to find someone else, in my opinion.