APACS stands for the Association for Payment Clearing Services, which was an industry body for banks and building societies in the United Kingdom that provided a forum for the collective development of standards and resources to facilitate payment clearing.
The 'Big Four' refers to the four largest firms in the world of accountancy and auditing, which include Deloitte, Ernst & Young, KPMG, and PricewaterhouseCoopers, as well as the major commercial banks in the UK such as Barclays, Lloyds, HSBC, and Royal Bank of Scotland.
A cheque that has not been presented for payment within a specific period, typically six months, rendering it invalid as the issuing bank will not honour it.
VocaLink is the company responsible for owning and operating the UK's national bank payments infrastructure. It works closely with Bacs, the automated payments scheme used by British banks, and LINK, the national network of cash machines.
