The UK Border Agency is warning people not to be taken in by scammers demanding cash in return for dealing with immigration cases.
The warning follows a report of an individual posing as a Border Agency officer and visiting a pensioner's home to ask for £1,350 to process his partner's visa.
The allegation is being investigated by the UK Border Agency security unit.
Jonathan Nancekivell-Smith, Director of Visa Services at the UK Border Agency said: "UK Border Agency officers do not visit homes to collect cash payments and we have referred these allegations to our security team.
"Anyone who is approached in this way should contact the police.
"Details of how to pay for visas are included with our application forms and further information is available on our website."
If you have lost money to a fraud like this, report it to Action Fraud.
Read more about the visa scam warning on the UK Border Agency's website.
Please note: Action Fraud is not responsible for the content on external websites.
To report a fraud, call Action Fraud on 0300 123 2040 or use our online fraud reporting tool.