Hi Domagoj,
Let me explain as briefly as I can.
Once you sign a contract you need to apply for purple certificate. You cannot start to work before you get the purple certificate.
What you need to do is apply for Purple Certificate via intra company transfer, this the corect route in your case and easiest. You don't need to have any language test, you just need sponsorship number (your company will do that), your contract/offer letter, passport and photos.
It will take some time for your company to get the sponsorship number issued. They need to be registered with Home Office as a sponsor in order to do this. If they are not registered they will have to get registered.
My company went via a solicitor who sent the documents by post. This is the longest possible route to take. The easiest way is to book yourself an appointment via the Premium Centre. Thing is when you go to book an appointment the system tells you there are no spaces available in next 45 working days; however, if you do this at midnight UK time on Sunday/Monday (or any other day) you will be able to get a slot as this is the time when they open up free spots. You then book a time and pay immediately.
You then go to Premium Centre and, providing you have all the necessary documents, you will get your card the same day.
There is no interview involved using route I have taken.
That's it really. I don't know other routes and I don't know this process in great detail.
Hope this helps. It is a bit of a drag but it's worth it
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