How can I check my credit score in the UK?

ClearScore provide a free monthly update, and no impact on your credit score. It also tracks your long term and short term debt, spending, and income. I've got no affiliation with them, but can recommend it.

You create free accounts with Experian (for Experian), ClearScore (for Equifax) and CreditKarma (for TransUnion). That covers the three main UK agencies, and will have no effect on your credit scores.

MoneySavingExpert has a free CreditClub which allows you to check your Experian credit score for free once per month and gives an eligibility score for various credit cards or loans.

"Credit Scores" are an over-simplification of the UK system, so it's worth understanding what happens behind the scenes.

We have four credit reference agencies, Equifax, Experian, TransUnion and Crediva. Each agency collects information about you, and sells that information to companies that may be considering offering you credit. The company then uses that information, along with other information you have provided, to decide if they are willing to take the risk of lending to you. Different companies will have different priorities. For example, if you're applying for a new credit card, the company may be concentrating on how many credit cards you currently have and how much of the available credit you're using. If you're buy a mobile phone contract, they might be more interested in whether you've been paying your current bills on time. That's why there can't be a simple "Credit Score".

Because each of the agencies operates independently, they collect the information in slightly different ways and may not all have the same information about you. It's therefore a good idea to check your credit file with each of them. Doing this has no impact on your credit score, and you can do it for free - there is no need to pay for the extra services that the agencies try to sell you. The three biggest agencies allow you to do this online, see ClearScore (Equifax), Experian and Credit Karma (TransUnion) websites. Crediva requires you to send them a letter. They are the smallest so could just be skipped unless you're having trouble getting credit.