This is the second time in as many months that NatWest customers have suffered from banking problems. In June the bank suffered major technical problems and millions were left unable to withdraw money, check their balances or make payments.
Nationwide has apologised after 704,426 customer's accounts were mistakenly debited twice. ITV News understands 50,000 people went into the red. NatWest has said they have resolved earlier issues with online banking and debit cards.