Client claims IS for himself and partner. Partner's found job, 16 hours a week. They have 4 children, 3 at school. Client has disability and cannot work, they get Disability Premium.
Better-off calculation shows, taking school meals into account, that they would be better remaining on IS and not claiming WTC. Can they do this or do they have to tell Tax Credits that partner is now working and accept the WTC?

Sorry, just seen other similar posts - there doesn't seem to be a straightforward answer.

I think the similar posts relate to a complicated interaction between WTC and income support if you try to claim them both at once. But it is perfectly permissible for the partner of someone claiming to work (in fact up to just under 24 hours a week) under the IS system, though in these days of child tax credit it can be hard not to go over the appliable amount. Presumably your disability premium does it for your clients.

So if they are really better off on IS, I can't see that there is a problem. Tax credits are specifically excluded from being notional income for IS.

And has anyone tried to give up WTC to claim IS instead, because of this exact situation?
I have a customer in this exact predicament!
I agree that TC is excluded from being notional income in terms of failing to apply for it, but what if customer deprives self in order to claim IS?!