German and former queen boarding British vessel (8)
I believe the answer is:
berliner
'german' is the definition.
(someone from Berlin)
'former queen boarding british vessel' is the wordplay.
'former queen' becomes 'ER' (Elizabeth Regina, ie Queen Elizabeth).
'boarding' is an insertion indicator.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'vessel' becomes 'liner' (liner is a kind of vessel).
'b'+'liner'='bliner'
'er' put inside 'bliner' is 'BERLINER'.
'and' acts as a link.
(Other definitions for berliner that I've seen before include "capital chap" , "Person from the German capital" , "European citizen < in trio" , "German capitalist" , "'Ich bin ein . . . . . . . .' (JFK)" .)