Keith Vaz, the chairman of the Commons home affairs select committee, said: “I am very concerned. The issue of cybersecurity is now considered to be one of the main areas of fraud and crime. We have urged companies to take much more seriously the threat of hacking. It is inexcusable that a company as important as eBay has failed to inform its customers immediately that this has occurred. We need a full explanation. We will be writing to them to ask how this happened and whether this problem has been resolved.”