Once the paperwork from a club for a transfer is received, it is checked against the Premier League and Football Association rules.
In some cases the transfer needs to comply with FIFA regulations, too.
If there are any issues the club are contacted for clarification or more information accordingly.
The Premier League will then advise the club if the player is registered or not and whether the signing is pending further to the receipt of additional documentation, for example, international clearance or an amendment.
This check is completed straightaway because clubs want to know as soon as possible whether or not all the necessary paperwork is in order.
It does get busy during the transfer window.
In one window recently, approximately 30 transfers came through in the space of an hour.
Premier League staff will not go home until everything is checked.
Also in this series
Part 1: What is the deal sheet in transfers?
Part 2: How do clubs begin the process of completing a player transfer?
Part 4: What is FIFA's Transfer Matching System?
Part 5: How does the work-permit process work for transfers?
Part 6: Rules governing the third-party ownership of players
Part 7: Is a fax machine used for transfers?
Part 8: How many loans are allowed by Premier League clubs?