The millionaire businessman at the centre of a decades-old divorce battle has said fighting the case has already left him with a bill of over £500,000.
The Supreme Court ruled yesterday that Kathleen Wyatt could continue with a £1.9 million claim from Dale Vince, even though she did not lodge a maintenance claim until more than 25 years after they had separated and nearly 20 years after their divorce.
Justices were told the couple met as students, married in 1981 when they were in their early 20s, and lived a New Age traveller lifestyle.
They separated in the mid-1980s and divorced in 1992.
In the mid-1990s Mr Vince began a business career and went on to become a green energy tycoon after launching a company called Ecotricity - said to be worth at least £57 million.
Ms Wyatt lodged a claim for "financial remedy" in 2011, but it was blocked by the Court of Appeal in 2013 before the latest Supreme Court ruling.
The 55-year-old hailed the decision yesterday as "important".
Speaking on BBC Radio 4's Today programme, Mr Dale said he was "frustrated" that Ms Wyatt was being allowed to "cash in a very old lottery ticket".
"There has been such a great passing of time. Our relationship ended 32 years ago which is an incredible passing of time," he said.
"We had a settlement 20 years ago but I cannot prove that because it was so long ago that not even the courts keep records.
"So the passing of time itself has allowed this claim to be brought."
Mr Dale said the Supreme Court only heard "one side" of the story about who cared for the couple's son because they were judging whether her "best case" constituted a valid claim.
"We both did what we could at the time. It was a very long time ago," he said.
"The son in question has been living and working with me for most of the last 17 years so I'm still taking care of him in a way - he is a grown man, but in a way.
"I think it is very wrong just to cash in what is in effect a very old lottery ticket on her part."
Mr Dale, who lives with his second wife in a Georgian fort, refused to say what his son thought of the case, but insisted he would continue to oppose the claim.
"I still think that the principle is very important, it is incredibly wrong," he said.
He said under divorce rules, he was footing the legal bill for both sides.
"I am actually paying her costs to take this to court, which is a very big sum of money," Mr Dale said.
"In this case 20 years after we divorced, 30 years after we split up I am having to pay her costs to get this to court. Which is bizarre.
"It is over half a million pounds so far."
Mr Vince told the Press Association that the law should be changed.
"There clearly needs to be a statute of limitations for divorce cases - a time limit beyond which a claim cannot be made. Such a thing exists in commercial law for good practical reasons. It's six years, which is plenty long enough to bring a claim," he said.
"Divorce law needs to catch up. The current situation is absurd."