You can apply for a visa extension as long as the total time spent in the UK is less than 6 months, so if you apply for a 3 month visa, but due to some unforeseen circumstances or you simply wish to stay longer, you may apply for an extension of up to a further 3 months. However there are instances in which you can remain in the UK for longer than 6 months: if you are undergoing medical treatment in the UK which has been paid for, and you meet the eligibility requirements you can stay in the UK for a further 6 months. Please note that any applications made must be done in the UK. 

There are a couple of ways in which you can apply for a visa extension, for further guidance and help please do not hesitate to get in touch if you are unsure about any applications that need to be made to Home Office or you require more information about our services.