But The Independent Group denies any wrongdoing.
Data helped Labour target marginal seats at 2017 election.
Eleven political parties were also issued with warning notices.
An investigation into how it happened is underway.
Parliament’s standards watchdog is investigating a “serious data breach” after a document containing details of MPs’ staff’s
John Cleese has branded the Daily Telegraph a Tory propaganda sheet, after it was fined £30,000 for breaking marketing rules
Ambulance-chasers will always be found circling like vultures around any corporate disaster, but three things about the customer experience really stood out for me in this crisis and neither were handled well by TalkTalk.
The privacy watchdog is investigating the online dating industry after claims that personal data was being sold to bolster
It's clear that nuisance calls and texts have become a daily problem for many people. They not only cause frustration, but they can even be distressing and intimidating. We've had more than 1,600 comments about nuisance calls and texts on our website and many of them had the same theme - 'why isn't something being done?' Our research also found that in the last three months, seven in 10 people received unsolicited calls and four in 10 an unwanted text.
Union activists have demanded action against a murky "blacklisting" website, which purports to show employers whether their