The International English Language Testing System (IELTS), which is one of the most commonly used tests and is partly owned by the British Council, recommends that a score of at least 6.5 is needed for any degree course.
Yet 58 of the 88 universities that responded to a THE Freedom of Information request say that their "standard minimum" requirement for undergraduates is 6.0, which IELTS says is "probably acceptable" for students on "linguistically demanding" training courses such as air traffic control, but not academic programmes.
The University of West London, Queen Margaret University and Glyndwr University have minimum entry requirements of 5.5, which IELTS says is "probably acceptable" for "less linguistically demanding training courses" in subjects such as animal husbandry and fire services.
Standards are higher for postgraduates, with no university accepting a score of 5.5, but 39 respondents say their minimum is 6.0.
However, many institutions point out that for some linguistically demanding subjects such as law or journalism, the entry requirements are higher at the undergraduate and postgraduate level.
Geoffrey Alderman, professor of history and politics at the University of Buckingham and a critic of standards in UK universities, said he thought that some institutions were setting English requirements "deliberately low in order not to discourage students".
Catch up as we go along
The survey also shows that £12.2 million was spent by universities in 2010-11 on English classes for international students, which equates to an average of £80 per student enrolled that year, according to the 59 institutions that answered this part of the FoI request.
There were significant variations in spending: the University of Chichester, for example, spent an average of £903 per international student enrolled, while the University of Bath (£260), Bucks New University (£228) and the University of Essex (£2) also spent significant amounts.
The figures encompass classes taken before degree courses began (pre-sessional) or during study (in-sessional), and only when students had already been accepted on to degree programmes.
Professor Alderman said that universities were "hoping that pre-sessional courses will bring [students] up to speed", but added that many institutions did not make such sessions compulsory.
Roger Brown, professor of higher education policy at Liverpool Hope University, said that the English entry requirements were "modest".
He added that the £80 figure "sounds on the low side" and said it was "unfair" to international students to expect them to combine in-sessional courses with their degrees and the process of settling in a new country.
Mark Walker, director of examinations at the British Council, stressed that IELTS' 6.5 minimum was a recommendation rather than an "absolute" requirement, and said that language ability was just one factor in admissions decisions.
He also said international students bring in billions of pounds a year to the UK economy and "we [the UK] are not in a monopolistic market".
Asked whether the income provided an incentive to lower requirements, Mr Walker argued that it did the opposite. "In order to be a successful business, you have to have happy customers" who do not struggle with their courses, he said.
A spokeswoman for Universities UK pointed out that institutions would not be allowed to recruit international students if they did not have high completion rates.
"It is in no one's interest for international students to come to the UK if they are unable to finish their courses because they are struggling with the language," she said.
Tongue-tied: readers' experiences of language gaps
Speaking of a Chinese applicant for an MA media course, a member of Times Higher Education's reader panel says: "His spoken English was very poor and he didn't appear to understand anything we were asking him."
However, he adds, the head of department said the student had been offered a place, saying, "'He'll do fine once he settles down'...Suffice it to say that the poor applicant didn't do fine."
Another panel member recounted: "Students routinely arrive with a 6.5 rating but often fall short of the standard required to keep up with undergraduate or postgraduate courses...group work is particularly challenging."
"I'm sure some of them have people to proof-read [essays] at the very least. In exams it is of course always difficult to assign a mark when English is poor," said a third THE reader panel member.