A former PhD student at Cambridge University has successfully challenged a demand by his local authority to pay council tax.
Cambridge City Council's policy was to grant exemption from the tax to PhD students for the first four years.
It claimed Dr David Feller had exceeded the time limit and that there were no "exceptional circumstances" for continued tax relief.
The High Court ruled Dr Feller had been wrongly charged.
Judge Timothy Corner QC ruled even though he did not attend regular classes he could still be in "full-time" education and qualify for exemption from council tax.
The test case is a setback for Cambridge City Council.
It had argued Dr Feller was liable for council tax as he was not required to "attend" formal courses at the university for a minimum 24 weeks each year and 21 hours each week.
In a ruling which broke new legal ground, Judge Corner said: "It seems to me in the ordinary use of language that a person can attend a course, or attend a university, without being physically present at a particular place for any length of time.
"In an academic context, it is a natural use of the language to speak of a person attending a course if he is subject to a degree of supervision, in some appropriate contact with the academic authorities, but doing the substantial part of his work in a library, or at home."