International law firm RPC said on 29 March that HMRC is "unlikely" to succeed in overturning yesterday's appeal win by BBC Match of the day presenter Gary Lineker over a £4.9m tax bill.
Partner Adam Craggs, head of tax disputes at international law firm RPC, said: "This decision provides yet another illustration of the complexities of IR35 and employment tax more generally.
"As so often in cases of this nature, the decision is highly fact-sensitive.
"The fact that the decision appears to turn on which of the partners in GLM (Gary Lineker Media) executed the contracts is superficially surprising, but in view of the case law cited to the tribunal (Memec v IRC  STC 754) appears ultimately to be correct.
"Those drafting the IR35 legislative scheme do not appear to have had the implications of a general partner being the intermediary at the forefront of their minds.
"HMRC have noted that they may appeal this decision. They may also consider legislation to correct what they will doubtless view as a lacuna, but given the time that will be taken for an appeal to be heard and determined and given the tribunal's findings of fact it is unlikely that any appeal by HMRC would ultimately be successful."
Lineker presents BBC's Match of the Day and used to also work for BT Sport.
HMRC said he was an employee of both broadcasters but yesterday's ruling by the Upper Tribunal (Tax and Chancery Chamber) concluded that he was a freelancer and had contracts with both broadcasters.
Tribunal Judge Brooks said in a statement: "The effect of my conclusions is that because there were direct contracts, between the BBC and Mr Lineker and BT Sport and Mr Lineker, the intermediaries legislation (IR35) does not, and cannot as a matter of law, apply.
"Accordingly, and notwithstanding GLM (Gary Lineker Media) being a partnership, that is the end of the matter and the appeal succeeds."
Lineker responded to the ruling on social media: "I had already paid all tax due at the top rate and happily so. I'm totally flabbergasted as to why I was expected to pay double. Thankfully justice was done."
A HMRC spokesperson said: "The tribunal has confirmed the off-payroll rules apply to partnerships, as we have always said.
"However, we do not agree with its decision that the rules cannot apply in this case and we're considering an appeal.
"It is our duty to ensure everyone pays the right tax under the law, regardless of wealth or status."
HMRC has 56 days to appeal to the Upper Tribunal (Tax and Chancery Chamber).