Can anybody give me the reference for a commissioner's decision (or higher court appeal decision for that matter) about the burden of proof in tribunals? I know it lies with the DWP, or LA, but I could do with a commissioner's decision to demonstrate this for an forthcoming appeal.
I think I had one Comm's decision on the subject in my collection but it's no longer there (filched by a former colleague, possibly) and it's not the easiest thing to look up on the commissioner's website. I have done a seacrh and found out some fascinating things about tribunal procedure (!) but not what I was looking for.

In what context is the burden/standard of proof at issue? There are MANY areas where the onus is on the claimant - particularly where an exception is at issue. Without the context, it's impossible to advise. At least not accurately.

For example, HB/CTB overpayments. In the first instance, the onus is unquestionably on the LA to demonstrate there is an o/p. However, if it is being argued the o/p was caused by an official error, the onus switches to the clmt to show s/he did not contribute to the cause of the o/p and could not reasonably have been expected to realise s/he was being overpaid.

The burden of proof is a common law one which runs as follows. He who alleges something must prove the truth of that allegation. So, I assert that I’m entitled to benefit. Thus I must provide information/evidence that I am so entitled. It is then up to the DWP/LA to provide information (i.e. legislation)/rebuttal evidence (i.e. a medical report) that my claim is ill founded.

Similarly (as Kevin says) if the DWP/LA allege an overpayment has arisen and is recoverable then it must make out its case with the claimant having the chance to refute the allegation at each stage.

Although the relevant party must make out its ground tribunals have been cautioned (see Baroness Hale in Kerr) against relying too much on notions of “burden of proof” which belong more properly in adversarial proceedings and to remember their inquisitorial function which is (in my words) ‘to get to the bottom of things’.

The LA made a decision that the claimant's tenancy agreement is not on a commercial basis, after paying him HB for 10 years on a series of shorthold tenancies, with virtually the same terms apart from occasional rent increases, with the same landlord. They made the decision after a fraud interview with the landlord about his own claim for Income Support and council tax benefit. They did not interview the tenant, but first suspended his HB claim for 4 months without giving him a reason, and then made a decision that he was not entitled to HB and had not been entitled for 10 years, based on "an interview with the landlord". The LA refused to give us a transcript of the interview because, they claimed, it contained information personal to the landlord and so it could not be revealed or they would be breaking the Data Protection Act.
There are exceptions to the protection of personal information under this Act, and we subsequently got a transcript of the interview, but only after we went to a TAS directions hearing with the LA's decision maker. (Since this option was available I had to try it before I could apply for judicial review against the LA).

Our contention is that it takes two to contrive a tenancy agreement and the LA had no business making such a decision without also interviewing the tenant.
(Other issues apart.)

Ok, that helps greatly.

If the LA's decision is non-commercial under HBR 9(1)(a), or "contrived" under HBR 9(1)(l), the onus is very much on the LA to show it had grounds for revising / superseding.

The administrative delays are not directly relevant to the substance of the decision, although it may be open to implication the LA wasn't terribly confident of its decision.

In itself, I don't think the LA has to interview any particular party before arriving at its decision. If the LA considers it has sufficient evidence / info to give grounds for revising / superseding at any given point in time, the decision can be made.

It's a bit unclear if its a non-commercial decision, or taking advantage ("contrived"). If the latter, it doesn't necessarily need two parties to "contrive". For example, in "Baragrove", the "blame" was laid fairly and squarely at the door of the landlord. The "Baragrove" principle has been successfully argued as recently as CH/136/2007 (a case I was involved with).

As for the IUC transpcript, there are now several Cmmrs/UT decisions which make it crystal clear a LA is supposed to provide ALL relevant info/evidence and, if it doesn't, the LA shouldn't be surprised if its case falls. In particular, CH/3240/2007 may be of interest (paras 16-20).

If any of the parties scream "breach of DPA" at the hearing, there are a couple of antidotes. Firstly, s.35(2) of the DPA makes it clear data is excluded from protection where it is provided for the purpose of legal proceedings and/or exercising legal rights. Further, even if the DPA is breached, the evidence is still (normally) admissible - see CH/4970/2002. Also see CH/3026/2007 where the Cmmr strongly suggests that if a LA wishes to withold info/evidence, it should ask for a Direction.

Hope the above helps.