Sounds exactly the same as this thread:
[url]https://hbinfo.org/forum/viewtopic.php?t=6947[/url]
Same case perhaps?
From the way the arrangement is described in that thread, it would appear that CMHT has facilitated a private deal between the claimant and landlord, and is underwriting it for the time being because of the benefit dispute. But HB will only be your responsibility if your Council (through any of its departments) is charging the claimant rent – if that is so, you reduce his rent by way of a rebate. Otherwise, it’s up to the other borough to pay rent allowance.
You could offer to assess HB on the other Council’s behalf under s134 of the Administration Act, but it is ultimately their case if my understanding of the rent liability is correct (i.e. a private tenancy or licence). Even if your Council was discharging homelessness duties when it fixed him up with the place, the thing that dictates HB responsibility is the payment of rent. You can only rebate what you are charging him yourselves, and oif you aren’t charging him rent it’s got to be a rent allowance paid by the borough in which he lives.