Has your credit score been hit by hidden rule change?

One of the easiest ways to build your credit score is to get yourself registered on the electoral roll. But The Guardian estimates 800,000 people have fallen off the list since changes were introduced – and that could have a negative impact on their credit scores.

Until recently, you registered to vote by household, so there was one form for everyone you lived with. Now, you need to register as an individual, and though many people were automatically transferred to the new system, more than three quarters of a million people are thought to have dropped off the register.

Why being registered to vote makes a difference to your finances

The main purpose for being on the electoral register is to give you the ability to vote in elections and referendums. But an additional benefit is it also helps you when you want to borrow money.

Being registered verifies your name and address, so when institutions and companies check your credit report, they've proof of who you are and where you live.

Not being listed, or having an old address, can make it difficult for lenders to verify who you are, and they might view applications as potential fraud.

How lenders use your credit score to decide whether to lend to you

The surprising times you can be credit checked

For many it's a surprise how often your credit score is checked. It's not just applications at banks for loans, mortgages and credit cards.

If you're after a new mobile phone contract, want to switch your energy supplier or get a new bank account, you are usually applying for credit, which means the company will check your score.

Though the tests usually aren't as strict as with the bigger borrowing applications, not being registered can make it more likely you'll fail the credit check – and get rejected. This can then damage your score, making future applications harder.

Are you on the electoral roll? How to check your credit report has the right details

Other ways to boost your credit rating

Once you've registered to vote, don't stop there in protecting your credit score. Here are some things you can do to boost your rating.

• Check the details on your report to make sure everything is accurate

• Avoid multiple applications in a short space of time

• Pay all your credit cards, mortgage and other debts on time

• Cancel unused credit cards, though consider opening a credit building card if you have a poor credit history

More tips to improve your credit rating

This article is provided by the Money Advice Service.