The Employment Appeal Tribunal has upheld an earlier Hull tribunal finding, which said the Redrow contract was a "sham" because it "did not seriously reflect the relationship between the parties".
The case was brought by Ucatt on behalf of two bricklayers who had been engaged by Redrow Homes (Yorkshire) under its subcontract for labour-only workers.
The appeal tribunal confirmed the original finding that "Redrow in effect wanted workers, but did not want to incur the legal obligation to pay holiday pay".
ADVERTISEMENTUcatt general secretary Alan Ritchie said: "I hope this case marks the end of companies building ever more detailed stratagems in the bid to avoid paying holiday pay.
"It has been repeatedly shown that once these contracts are exposed to legal scrutiny, they collapse faster than a house of cards."
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