Clutching at straws a bit here I suspect. Due to MH problems client has been a virtual recluse for several years and was unknown to professionals, no relatives etc. Lived on tiny occupational pension, claimed no benefits, now has c/tax arrears of £3062. naturally we will ask for CTB to be backdated as far as possible, but I was thinking about SMI exemption to go back further. A condition is that the person must be entitled to (though not necessarilly in receipt of) a qualifying benefit (CPAG c/tax handbook). presumably this means "has applied for and been awarded at least underlying entitlement". Any chance it might mean "would have been iro if he had applied"?

Who's going to decide if the client "would have been iro if he had applied"?

In my view, the crux is the word "entitlement".

Without a claim, there can be no entitlement. Therefore, barring case law suggesting otherwise, I'm inclined to concluding that the "would nave been...." argument is doomed to failure.

Paragraph 3(1) of The Council Tax (Discount Disregards) Order 1992 states; -

“The condition prescribed for the purposes of paragraph 2(1)(c) of Schedule 1 to the Act is that the person in question is entitled to one of the qualifying benefits listed in paragraph (2) below”.

So, as indicated above, without a claim there cannot be entitlement. Note, this is distinct from other discount provisions, which are not dependant on being in receipt of certain benefits, where status can be backdated indefinitely as long as it can be evidenced.

And of course DLA cannot be backdated.

I agree about the discussion on the meaning of "entitled", which in the DLA/AA context can be opposed to "payable" eg because of hospitalisation in excess of 28 days. It would be nonsense to deprive a person of this exception just because they were in hospital for a long time - indeed, especially because they are likely to be.

I have dealt with a similar case and got SMI backdated to the date of diagnosis for a pensioner on the basis of paragraph 3(3) of the The Council Tax (Discount Disregards) Order 1992 inserted by SI 636/1996

"(3) The requirements in this paragraph are—
(a) that the person in question has reached pensionable age as defined for the purposes of Parts I to VI of the Social Security Contributions and Benefits Act 1992<3>, and
(b) that had he not reached pensionable age he would have been entitled to one of the benefits listed in paragraph (2) above

I argued that they would have been entitled to incapacity benefit, but couldn't claim now or obtain a determination because of their age.

I also argued that the person would be deemed to be incapable of work by virtue of regulation 10(2)(e)(viii) of the Social Security (Incapacity for Work) (General) Regulations 1995

"that a doctor approved by the Secretary of State has certified that he is suffering from any of the following conditions—
....
(viii)a severe mental illness."

hope this helps