1. Does not guarantee accuracy: A trial balance only confirms that debits and credits are equal, but it doesn't guarantee that all transactions have been correctly recorded. For example, a transaction could be incorrectly posted to the wrong account.
2. Errors of Omission: The trial balance will not detect errors of omission, where a transaction has not been recorded at all. The debits and credits may still balance, but the financial records are incomplete.
3. Errors of Principle: Similarly, errors of principle, where a transaction is recorded in the wrong account, will not be detected by a trial balance. The debits and credits may balance, but the financial statement will be incorrect.

Compensating Error: A compensating error occurs when a debit and a credit error of the same monetary amount are made in the accounting records. For example, if £100 is debited instead of credited, and £100 is credited instead of debited, the total debits and total credits remain the same. This results in the trial balance being balanced.

Omission Error: An omission error occurs when a transaction is completely failed to be recorded in the ledger. For example, a £50 sales transaction is never entered. This results in either a debit or a credit difference in the trial balance, leading to an imbalance. The total debits will be less than the total credits (or vice versa), causing the trial balance to be unbalanced.

Effect on Trial Balance:

A trial balance is a list of all the ledger accounts and their balances on a specific date. It's essentially a summary of all the account balances.

The purpose of a trial balance is to check the mathematical accuracy of the ledger. It ensures that the total debits equal the total credits. If they don't, it indicates an error has occurred during the recording of transactions, such as a mistake in posting to the ledger. It's a crucial step in preparing the financial statements.