1 in 3 in the UK people overpay income tax and actually pay the government more than they should. It is the money that you overpay that we are able to reclaim for you. This money is legally yours and you are fully entitled to ask for it back. Everyone has the right to claim their tax refund regardless of nationality and it won’t affect your visa or residency status.
In the UK, everyone is given a tax-free allowance. For the tax year ending 5th April 2013, this tax-free amount is £8,105. This amount is divided by 12 equal portions (to relect 12 months in the year) and every pound that you earn over this monthly amount is then taxed at 20% (up to a yearly salary of £42,475).
Sometimes, when changing employers, employees may be given a BR or OT tax code, which means that they are not given their personal allowance entitlement. First thing to do is to talk to your employer's payroll department. In most cases, they would still be waiting for HMRC to communicate your new tax code to them, so your employer can use it when working out your wages. Provided that you gave your new employer parts 2 & 3 of your P45 in the first place, this should normally get resolved within 6-8 weeks, and your overpaid tax would automatically get refunded through your wages.
But sometimes it doesn't get resolved. It is a good idea then to contact a tax agent - a tax specialist - like TaxRefundPro so we can ascertain if you are due a refund. Provided you give sufficient information about your earnings and the tax you paid, we should be able to tell you instantly if you are due a tax refund, and if yes, how much. However, please note that a tax agent cannot reclaim your overpaid tax within the same tax year. Except if you are permanently leaving the UK, tax agents can only submit a claim for a tax refund for tax years that have already lapsed i.e. 2012/13 tax year is the first tax year we can submit a claim for a tax refund