Voting in elections in the UK does not require you to bring any form of ID to the polling station. Why is this? Could someone vote multiple times by giving different addresses?
Registered voters are issued with polling cards, usually by post. However you do not need a polling card to vote as long as you are on the electoral roll.
In polling stations where there are a small number of voters (eg in small villages) and the staff know you by sight they will often just allow you to vote if you give your name. Presumably there is some risk of fraud here but you are running as serious risk of getting caught and the associated consequences if you get caught if the person you are impersonating has already voted or turns up to vote later.
It is also worth noting that individual poling stations in the UK all tend to serve quite small areas and you need to talk to the officers to receive your ballot paper so the chances of being noticed if you try to vote more than once are high.
In reality significantly influencing any vote by impersonation would require a huge and centralised logistical effort and the political and legal consequences for the party trying it would be catastrophic if they got caught.
To pull this off you would need to be able to identify individuals who are unlikely to vote and find large numbers of people willing to risk serious criminal penalties to help you.
Voting in elections in the UK does not require you to bring any form of ID to the polling station. Why is this?
Because there is no form of ID that everyone is required to have.
There is an argument that insisting on, say, passports or driving licences, would discriminate against the poorer in society, as they are less likely to have either.
Could someone vote multiple times by giving different addresses?
If an elector is registered to vote in two different electoral areas, they are eligible to vote in local elections for the two different local councils. However, it is an offence to vote twice in any one election. Such an offence could result in a fine of up to £5,000.