Hello, I'm a medical doctor MBCHB Uganda, is it possible to specialize while serving in the British army?

Hello,

Yes you can specialise as a doctor serving in the British Army. Each year the Army decides how many trainees it needs for each specialty, and doctors already serving as General Duties Medical Officers can apply. Some specialties such as Paediatrics and O&G are unlikely to be available. More commonly General Practice, General Surgery, Emergency Medicine, Anaesthetics, Public Health, General Medicine and Psychiatry are popular choices.

In regards to applying from abroad there also a couple of things to consider. Not all roles are available to those applying from outside the UK (please see the Army jobs website for what roles are available https://apply.army.mod.uk/how-to-join/can-i-join/nationality ).
If you have not practiced medicine in the UK you are likely to be asked to display your foundation competencies prior to joining. This involves completing the 2 year foundation programme in the NHS. Without this the Army is unlikely to consider your application, but more importantly, you will be unable to apply for specialty training in the UK.

I hope this answers your question.