TAX officials have launched a crackdown on suspected fraudulent credit claims.
HM Revenue and Customs (HMRC) is sending out 12,000 letters to self-employed people who are claiming tax credits, asking them to supply evidence to support their claims.
The action follows examination of tax credits by HMRC teams.
Failure to report any changes in income can result in overpayments and claimants have to pay back the money. They could also be given a penalty and in the case of deliberate fraud, they could face criminal prosecution and imprisonment.
There are currently around 3,200 self-employed people in Northumberland claiming tax credits.
For information about the system call the tax credits helpline on 0845 300 3900.