Switch (debit card)
Switch was a debit card in the United Kingdom which was renamed Maestro by its owner MasterCard in 2002. Prior to its renaming it had built a strong brand within the UK and people continued to use the name to mean debit transaction for a number of years after it was discontinued.
Switch was launched in 1988 by Midland Bank, National Westminster Bank and the Royal Bank of Scotland as a multifunction cheque guarantee and cash card. The brand was merged with Maestro, an international debit card brand owned by MasterCard, in late 2002. This merger was referred to as the "penguin wedding," due to its distinctive advertisements of penguins in different international settings created by Joel Veitch. Since then, Switch has been out of circulation and banks migrated customers from Switch to Maestro.
The merger was also intended to increase the acceptance of foreign Maestro cards in the UK. However, despite the Maestro brand name, point of sale transactions in the UK were still processed by Switch Card Services Limited. Consequently many retailers who advertise that they accept Maestro could only accept UK-issued cards, i.e. former Switch cards. In 2011, MasterCard aligned UK Domestic Maestro with the standard international Maestro proposition, ending its status as a separate card scheme. This change also led to the discontinuation of the Solo (debit card). 
Switch/Maestro cards issued by certain banks, notably the HSBC group, carried an issue number on the bottom of the card corresponding to the number of times a card had been issued on a particular account. This was usually because the current account number the card is linked to actually formed a large part of the card number, and therefore the card number could not be readily changed in case of loss or the card expiring.
Despite the formal brand remaining defunct for a number of years, the term "Switch" was commonly used to refer to Maestro cards in the UK, consequently they are referred to as Switch/Maestro.
In January 2009 First Direct and HSBC discontinued the use of Maestro card, issuing Visa Debit cards to new customers and a gradual roll-out throughout 2009 to existing customers. In September of the same year, the British arms of the National Australia Bank, being the Clydesdale Bank and the Yorkshire Bank, started the process of replacing the Maestro card with a Debit MasterCard for their current accounts, except for the Readycash and Student accounts, for which the Maestro card continues to be issued. Likewise, in the same month the Royal Bank of Scotland Group (Europe's largest debit card issuer which includes the NatWest, Coutts and Ulster Bank brands) switched from Maestro to Visa Debit, a process that will take two years to complete. This effectively means that practically no UK banks will be issuing Maestro cards, except in Northern Ireland.