Thousands of people working in the UK, do so for International Companies. Many are UK Residents, permanently based in the UK and do not have the need to travel, however a percentage will be either based in the UK with a working visa from abroad or a working visit on a short-term basis, maybe even for a few days. There are various types of organisations, from those Primarily focused on profit-making to International Charities. Either way some of these will require a form of Police / criminal check dependant on the role and government regulations.
International Organisations and charities whose employees work closely with children and vulnerable adults, have a duty of care to the safe guarding of those under their protection. They will need to provide for enhanced DBS checks to be carried out in the same way a solely UK based company would. Foreign Nationals with fixed term contracts would perhaps have to supply a DBS check or equivalent from both their residential country and after a time, the UK. This would be the responsibility of the Organisation to ensure this was in place, although the individual may need to request the check from their country of Origin dependant on the governing requirements.
Although International Organisations are required to adhere to the governments requirements where that branch is based, they may also request the employee obtain a Basic or Standard Disclosure, or equivalent, prior to taking up a role within that organisation even if the government regulations do not require it. Many organisations now ask employees to obtain a form of criminal check as part of the application process and those who do not provide one or have not disclosed any unspent convictions could be refused employment.