Students seeking accommodation are being warned about a bogus landlord scam on the internet.
Fraudsters are trying to tempt students to provide their bank details or send money to secure properties - only for them to discover no such house or flat exists.
In a review of a recent week's worth of reports on internet-related crime, the Metropolitan Police found almost a third involved this sort of ruse.
Det Sgt Chris Felton from the Met Police's Fraud Prevention told the BBC: "Things to watch out for are adverts where there are no telephone numbers or where the only email address is a free one - a Hotmail or Google email address - where you're not sure really who you are dealing with.
"If you are being asked to send money up front without being certain the property exists, then you need to be very, very careful.
"Think once, think twice, ask some friends, get some advice and if you're ultimately not happy don't send any money."
The scam typically involves advertising bargain properties on free listing websites.
Victims are told by the "landlord" the property can only be viewed if they give their bank account details, and the money is then stolen.
One Canadian student told how he was conned out of £1,000 after transferring the money for a London property into an apparent third-party account.
When he arrived in London, the property did not exist and he was unable to trace the "landlord".
The National Union of Students (NUS) is advising students to use their universities for accommodation guidance.
Ben Whittaker from the NUS said: "There are plenty of houses out there, plenty of stock.
"Go to your universities, your student unions. They will have approved housing lists. Even if your hall of residents teams can't accommodate you they will often point you in the right direction.""