The best mortgage rates are typically offered to borrowers with larger deposits and the highest credit ratings. If you want to secure a decent rate, it may well be worth building your credit score before you consider applying for a mortgage.
There are a few ways to help improve your credit rating, including:
Registering on the electoral roll.
Checking your credit report for any errors or out-of-date info.
Always paying your bills on time.
Cancelling any unused accounts and cards.
Avoiding applying for different types of credit over a short period of time.