I'm a citizen of Belarus, therefore requiring two different visas to enter Schengen area and the UK. My passport expires sometime soon - I know I can use a valid Schengen visa in a cancelled passport together with a current one, so I consider renewing the passport and keeping the old one. Then, I want to get a UK visa into my new passport. The intended travel itinerary is as follows:
Belarus -> Schengen area -> the UK -> Schengen area -> Belarus
My question is, may I run into problems going from Schengen to UK - i.e. does the UK check the visa of the state I arrive from, and if so, do they accept it if it's in a cancelled passport? Or, perhaps, any other caveats on other legs of my journey?