From BBC News
Tesco Bank's chief executive has blamed "a systematic, sophisticated attack" for the money taken from 20,000 of its customer accounts.
Benny Higgins said the bank knew "exactly" what the attack was, but could not say more because it was part of a criminal investigation. He said all affected customers would be refunded by the end of Tuesday.
About 40,000 accounts saw suspicious transactions over the weekend, of which half had money taken.