UKBA has announced changes to the immigration rules for over-stayers that come into effect from 1st October 2012. Previously if you over-stayed in the UK you were permitted to make a new extension application in the UK, even though your immigration permission had expired. However, under the new immigration rules, if your immigration permission has expired more than 28 days ago, if you apply for an extension from the UK, your application will be refused. This means that if you have over-stayed in the UK for more than 28 days you need to go home to make a new application. If you have over-stayed in the UK by more than 90 days you cannot make a new application from the UK or from overseas which means you would be subject to a 12 month ban from returning to the UK.
If you make an extension application in the UK while your immigration permission is still valid and your application is rejected you will be classed as an over-stayer from the date that you are notified that your application has been rejected, not from the date that your immigration permission expired. The date you are considered to have been notified is the second day after the date on the letter from UKBA.
从2012年10月1号开始，如果你的签证过期28天以上，你就必须回国签证了。如果过期90天，不好意思，你将会在未来的12个月里面无法再拿到英国的任何类型的签证。
更正：如果当你收到你的签证时，你的原始签证已经过期，那么你就从拒签信上的日期的第二天开始算是overstayer了。如果你的原始签证没过期，那么你不是overstayer。之前的理解的确有问题，不好意思啊
