The personal details of thousands of people may have been compromised after a data breach at one of the country's biggest housing associations.
Newcastle-based Home Group said it "acted quickly" to warn about 4,000 customers involved.
The charity provides rented homes to more than 116,000 people in 55,000 properties in England and Scotland.
It said the breach involved customer names, addresses and contact information, but no financial data.
The organisation said the breach was identified by a third party cyber security expert and affected customers in properties all over England, including those in North East, North West and Yorkshire.
It said he issue was resolved within 90 minutes.
Whoever was responsible would have needed "expert cyber security knowledge", a spokesman said.
Chief financial officer John Hudson added: "We were made aware of a potential data vulnerability and immediately responded to and resolved the issue.
"We have a robust incident response protocol in place to deal with situations such as this, which meant the vulnerability was identified and fixed extremely quickly.
"We have contacted all customers affected and I want to reassure all our customers that their information is secure and that we follow strict guidelines and protocols when it comes to data sharing and cyber security."