When you are buying a property there are a number of processes that you will need to go through to ensure that it is all legal and correct. This is why when you buy a property, you will need a conveyancing solicitor to deal with this side of things.
There are also other checks that are done, and you may need to give evidence of some things due to the fact that the property market in the UK is something that money launderers will try to exploit. Because money that is obtained illegally can lead to the police catching these criminals, investing the money into property is a way that they can get rid of it and therefore any links that might tie them to their crimes, whilst still having something to show for it, which they can then sell at a later date and have the money from.
This is why now if you are buying a property in the UK, there are checks done that prove you are who you say you are – an AML ID check like this www.w2globaldata.com/regulatory-compliance-solutions-and-software/aml-id-checks will be done.
The estate agent will also ask that you provide proof of where the funds to buy the property are coming from. If you are getting a mortgage this is easy to do, as the bank will just provide proof of your mortgage offer, or if you are buying the property with savings or inheritance you just need to provide the documents that back that up.