Some banks or building societies will allow an executor of a will to access the banks accounts of the deceased without a Grant of Probate, only requiring a death certificate. This typically applies to smaller estates, with no inheritance-tax liability or with jointly owned assets.
Larger estates and more complex cases with solely-owned assets typically go through the Probate process, so legal authority to manage the account requires a Letter of Administration or Grant of Probate; however, small amounts of money may be released from the deceased’s accounts to the executor as interim payments.