Controversial "conditional unconditional" university offers will be banned until September 2021, under new rules announced by an education regulator as a temporary response to the coronavirus pandemic.
Such offers give students a place - regardless of their A-level grades - on the condition they make the university their firm first choice.
But updated rules from the the Office for Students (OfS) prohibits any university from giving out the offers - or making false or misleading statements with the intention of discouraging students from attending other institutions.
Universities who breach the rule change could be fined more than £500,000.
The condition has been introduced in consultation with the higher education sector with a fixed end date, according to the OfS.
The new rules also still allow universities to make "contextual offers" to students from disadvantaged or underrepresented backgrounds - who may get lower grades than required - to recognise the different circumstances around their results.
A recent report found that the teacher assessment system - in place of cancelled exams - could negatively impact black, Asian and minority ethnic (BAME) pupils and those from more disadvantaged backgrounds.
The rule changes come amid a sharp increase in "conditional unconditional" offers in recent years.
Data published by Ucas earlier this year showed that in 2019 there were 35 universities and colleges where at least 1 per cent of offers made were the controversial "conditional unconditional".
Critics have slammed the practice due to concerns they encourage students not to work hard to get the best A-level results.
Nicola Dandridge, chief executive of the OfS, said concerns about the offers are "even more acute" given the disruption of the Covid-19 crisis.
"Our concerns are even more acute in these exceptional times with the shape of the next few months and years still very unpredictable, and information, advice and guidance less readily available than it may normally be," she said.
"However, we have ensured that the condition explicitly permits unconditional and contextual offers that are clearly in students' interests, and which support the transition into higher education for the most disadvantaged students.
"Students can also be reassured that they should not expect to have any offers that they have already received withdrawn, and where there are good reasons for them to receive an unconditional or contextual offer in future, there is no reason that this cannot go ahead."
She added the "necessary and proportionate" changes were designed to "avoid instability" during the pandemic but added they would not continue past September 2021.
Universities Minister Michelle Donelan described the offers as "potentially damaging practices," adding:
"There is no justification for conditional unconditional offers and I welcome the strong action against these potentially damaging practices while the sector navigates this uncertain period, and hope to see this continue beyond 2021.
"I do not want students to be taken advantage of and feel pressured into making a major life decision which might not be right for them."
The University and College Union (UCU) also backed the move for a "fairer admissions system".
It said allowing applicants to apply after they received their results would be better for students and remove the "gamble" of predicted grades.
A Universities UK spokesperson added: "It is vital that the admissions process remains fair, consistent, and in the best interests of all students and it is right to have temporary stability measures at this unprecedented time."
Coronavirus: Everything you need to know