I have a friend who has a primary and secondary employment where both have the tax code of something like 489L ie the personal allowance. She has worked at the primary employment for some years but only for the last 2 years at the secondary employment. She has completed forms given to her by her newer employer but was given the personal allowance tax code rather than BR which I believe she should have been given. She pays through PAYE and doesn't fill in a tax form.
My understanding is that the newer employer is ultimately liable for the uncollected tax. She has done everything in good faith and is worried about paying back tax for last year. This error has only been found as a result of assessing her financial position. She is of limited means and in receipt of WTC etc. What would her position be as we can be sure the proverbial will hit the fan shortly as she's changing employment soon.