Readers' forum : Here or there?

I have been asked to represent an architect who is based in Europe but is carrying out work in the UK. To avoid identifying the particular country involved let us say that it is Ruritania which is an EU member state. So my client is an architect based in Ruritania but who is carrying out some work for the Ruritanian embassy in London. My main concern is VAT. The client thinks he must register for UK VAT but I cannot understand why because his income from the job is much less than the UK registration threshold of £85 000.

I also wonder whether an embassy building is linked to its own country in this case Ruritania under special rules. So if it is a Ruritanian customer receiving supplies from a Ruritanian business surely the easy solution is to charge Ruritanian VAT....