As many as a third of house sales could collapse on 31 March unless the chancellor takes urgent action to change the stamp duty holiday.
Rishi Sunak brought in the tax break - worth up to £15,000 on home purchases - in an effort to get the rpoperty market moving again after lockdown.
However, it's proved so popular that everyone from lawyers to surveyors to mortgage providers have been swamped.
That means an awful lot of people might discover that, while they thought they were getting a tax break, their house purchase misses the March 31 window and they face a bill of thousands of pounds they hadn't budgeted for.
The Guild of Property Professionals found almost a third of buyers (31%) said they would very likely cancel their move if they had to pay stamp duty, with another 43% saying that they would likely do the same, the Sun reports.
Guild of Property Professionals boss Iain McKenzie said: "If the deadline remains as it is, only a quarter of the sales agreed in January will complete in time.
"With 140,000 more people waiting to complete sales than this time last year, there will be a significant number of buyers who will have to find additional money for stamp duty if they have not budgeted for it."
He called for either an extension of the tax break or a "phasing out" period to try and stop the sudden withdrawal forcing buyers to pull out and chains to collapse.
Other figures out today from mortgage broker Trussle warned that, with just 100 days until the deadline hits, transactions are being held up for a variety of reasons - including delays with surveys, conveyancing, mortgage lending and the Christmas period.
The time to get a mortgage approved has more than doubled, for example, from 10 days last year to 22 now.
That could leave many buyers potentially needing to find an extra £15,000 to complete their purchase.
Miles Robinson, head of mortgages at Trussle, said: "The stamp duty holiday in England and Northern Ireland has been a lifeline for buyers and lenders alike, giving a much needed boost to the market.
"As the deadline approaches it’s important that customers feel in control of their purchase and avoid any unwelcome surprises at the end.
"There has not yet been an agreement to extend the stamp duty holiday, or modify it in a way to allow those who exchange before this date to benefit.
"Therefore, it’s important that borrowers are equipped with as much knowledge as possible, so they can make an informed decision on their house purchase.”
