Belgium is one of the European nations and anyone seeking to move from London to Belgium should not have any problem in getting this done. You will have to present yourself at the Belgian embassy in London and you will have to go through the visa interview. If you are able to procure visa, all well and good. But if you are not able to procure visa, you may have to delay your move to Belgium from UK untill another time.
The only thing that may prevent a quick approval of your visa to Belgium, from London is if your papers are not in order. But if your papers are in order, you should not have any problem in moving at all. The Belgian embassy located in London will ensure a quick approval of your visa and you will be in Belgium before you know what is happening.
At the visa office, you will be queried on several things. One of them includes the issue of accommodation. If you do not have a reliable accommodation where you are going to stay when you arrive at Belgium, you may never be allowed to enter into the country from London. Aside this, you also need to provide evidence of what you want to go and do at the country.
If you are going to work there, you may be expected to provide the address of your new employer at Belgium. if you are going on vacation, you should provide an evidence of where you are visiting. If you are going to study, you will surely be required to provide your admission letter. Things like these become essential before you can enter into any other country from UK or any other country the world over.
You may also take some time to learn the Belgian language before you leave London UK.