Verifying bank details is usually attempted in the wrong order. People start with a lookup, which proves the least, and finish with a telephone call only if something already felt wrong. Reversing that order costs a few minutes and removes almost all of the risk, because the checks differ enormously in what they can establish and only one of them reaches a human who knows the answer.
Ranked by what each one proves
A format check proves the digits could be real. A modulus check proves the account number is arithmetically consistent with its sort code range, which mostly catches typing errors. A name check asks the receiving bank whether the name you typed matches the account and answers before the money moves, which is the first check that reaches the other institution. A telephone call to a number you already held proves that the person you think you are paying is the person who gave you the details. Only the last two are worth much.
The failure mode this exists to stop
Invoice redirection works by looking like housekeeping. A supplier you already pay sends a message saying their bank has changed, and the new details are perfectly valid because they belong to a real account that the fraudster controls. Every arithmetic check passes. The name check is the first thing that objects, and a telephone call on an old number settles it. This is why a change of details should be treated as an event needing positive confirmation, not as an update to apply.
What to do as the payee
Make yourself easy to verify. Print the exact account name beside the sort code and account number on every invoice, and say it is the name the account is held in, so that payers do not get a close match warning from a trading name. Publish your bank details in one place and tell customers you will never change them by email. If you do change bank, tell people by a channel that predates the change and expect to confirm it by telephone.
Where a lookup still helps
A lookup is useful for orientation rather than assurance. It can tell you which institution a code belongs to where that is published, which is handy when you are reconciling a statement or identifying an unfamiliar direct debit. It cannot tell you who controls an account. This site publishes what each bank states about its own identifiers, quoted and dated, and says plainly when a bank publishes nothing, which is the honest shape of what a lookup can give you.
Questions people ask about verify bank details
What is the strongest way to verify bank details?
A telephone call to a number you already held, combined with the name check your own bank runs when you add the payee.
Does a modulus check verify anything about the owner?
No. It is arithmetic on the digits and never contacts the receiving bank.
A supplier emailed me new bank details. What should I do?
Do not use them until you have confirmed by telephone on a number you held before the email arrived. This is the most common shape of payment fraud.
Can I verify details for an international payment?
There is no cross border equivalent of the UK name check in most corridors, so confirm with the payee directly and send a small first payment.