The bank apologised to Mr Jetley in a statement
A man who chose "Lloyds is pants" as his telephone banking password said he found it had been changed by a member of staff to "no it's not".
Steve Jetley, from Shrewsbury, said he chose the password after falling out with Lloyds TSB over insurance that came free with an account.
He said he was then banned from changing it back or to another password of "Barclays is better".
The bank apologised and said the staff member no longer worked there.
Mr Jetley said he first realised his security password had been changed when a call centre staff member told him his code word did not match with the one on the computer.
"I thought it was actually quite a funny response," he said.
"But what really incensed me was when I was told I could not change it back to 'Lloyds is pants' because they said it was not appropriate.
"I asked if it was 'pants' they didn't like, and would 'Lloyds is rubbish' do? But they didn't think so.
"So I tried 'Barclays is better' and that didn't go down too well either.
"The rules seemed to change, and they told me it had to be one word, so I tried 'censorship', but they didn't like that, and then said it had to be no more than six letters long."
Mr Jetley said he was still trying to find a suitable password which met the conditions.
He said his dispute with the bank started over some travel insurance, but that issue had been dealt with by managers independently.
A statement released by the bank said: "We would like to apologise to Mr Jetley.
"It is very disappointing that he felt the need to express his upset with our service in this way. Customers can have any password they choose and it is not our policy to allow staff to change the password without the customer's permission.
"The member of staff involved no longer works for Lloyds TSB."
Lloyds TSB stressed there was no security lapse in this case.
A spokesperson said: "On the majority of transactions advisors cannot read customers' passwords.
"In this case it was a business banking customer using a system where more than one person from a business can check their balance.
"In these cases an advisor can read the full password.
"But if such customers require more complex transactions, then full security procedures apply and advisors cannot read secure information."