This writing attempts to clarify in basic and simple terms how you can appeal against an immigration decision made outside the UK and the processes involved

The information is taken from the specific UKBA webpage Appeals - visas and entry clearance, the relevant links and also immigration policy and law.

The most common applications that have full rights to appeal are either direct family-visit visas or visas to settle permanently within eligible sponsors already settled in the U.K.
Family includes spouses, dependents, dependent children of spouses, and fiances of permanent residents or citizens of the U.K, as well as some other blood relatives that have settled, refugee or humanitarian protection status in the UK.
If you applied for and were denied another kind of visa, such as a temporary or permanent worker visa or an extended or working holiday visa, you may not have appeal rights. But if you do have a right to appeal, it will be stated on the written notice of visa denial.

How to Appeal
If you were granted full rights of appeal, the Entry Clearance Officer will provide you the following documents:-
- a written notice of refusal, which will tell you why your visa was denied
- a notice of appeal (form IAIT-2), which you must fill in explaining why you don't believe you should have been denied
- a guide that will explain how to fill out the form IAIT-2 and where to send it.

If you have any supporting documents that you did not include in your original application but wish to include now, include these with the completed form IAIT-2.

A 'Word' version of Form IAFT2 can be downloaded from here
Here is an example of A Guide to Completing IAFT-2 Appeal Form

Where to Appeal
The guide to completing form IAFT2 provides details of where to send your completed form.
In cases where a British mission overseas denied your visa application, you can post to:-

First-tier Tribunal (Immigration and Asylum Chamber)
PO Box 6987
United Kingdom

Your appeal form must be received within 28 days of the date you were served with the notice of decision.

Type of Hearing
You will need to decide which type of hearing you wish to have undertaken.
"On papers" means that the appeal will be decided on the information you provide on the appeal form and any other documents submitted as evidence.
"Oral hearings" take place in the UK and mean that the applicants sponsor and / or representative may attend.Oral hearings are informal affairs and allow the applicants sponsor and/or representative to 'have their say'.
Personally I believe Oral hearings to be much better in that their is a flexibility for nuance, meaning and understanding.

Time Frames
You must return your AIT-2 form (the notice of appeal) to the AIT within 28 days of receiving your notice of refusal.
If your application was to visit the UK, your appeal may take four to six months to process.
If your application was to settle permanently in the UK, your appeal may take take longer.

Process of Appeal Applications
Once the AIT has received your appeal form, they will send you a notice of receipt. Once the visa section receives this notice of receipt, the Entry Clearance Manager will review the decision to deny your visa, based on evidence you provided in your form AIT-2, along with any new supporting documents you provided.
If the Entry Clearance Manager is satisfied that your application now meets the requirements for entry, he will overturn the decision to deny you, and your clearance to enter the UK will be issued.
If the Entry Clearance Manager does not overturn the decision, an Entry Clearance Officer will write a statement explaining why the decision to refuse your visa was upheld. This will be mailed to you by the AIT.

Immigration Appeals
If your immigration application is unsuccessful you may have a further right of appeal.
Usually you will be notified of your right of appeal in you immigration decision letter from the UKBA or the Entry Clearance officer.
Such appeals are heard in the UK in a number of centres around the UK.

There are two tribunals:-
- a First-tier Tribunal
- an Upper Tribunal.

There is an Immigration and Asylum Chamber in each.

The Immigration and Asylum Chambers hear appeals on asylum, immigration, and nationality matters.
The role of the First-tier Tribunal is to hear and decide appeals against decisions made by the UK Border Agency's officers in the UK or at diplomatic posts abroad who can issue visas.

One or more immigration judges may hear an appeal.
They are sometimes accompanied by non-legal members of the tribunal. Immigration judges and non-legal members are appointed by the Lord Chancellor and are independent of the government.

If you make an appeal, you will usually attend the hearing with your legal representative. The UK Border Agency will also have a legal representative at the hearing.

The immigration judge, or panel, will decide whether your appeal against our decision is successful or not (this is known as the decision being 'allowed' or 'dismissed'). The tribunal's decision will be given to you in writing. It is called a 'determination'.

In certain circumstances you may be able to challenge a decision made by the First-tier Tribunal by applying to the Upper Tribunal.
The UKBA may also apply to the Upper Tribunal to challenge a First-tier Tribunal decision.

If an appeal has been considered by the Upper Tribunal, in some circumstances it may be possible to challenge the decision by applying to the Court of Appeal.

If you are confident in your appeal you should always consider seeking guidance from a level 3 immigration advisor who is able to carry through the full appeals process right up to Court of Appeal.

I am not a immigration advisor.
I have never been through an appeals process.
Hopefully, those with practical experience will take some time to contribute what they can in terms of the facts they have experienced.
Lets keep it as concise and factual as possible to give the very best information we can to help those in these awful and very stressful circumstances.

Re-counting actual tribunal experiences is considered to be factual so pease don't anyone be shy.

Good luck to all.