KLF
Albion Boleh!
Embassies and High Commissions are primarily there for presence for the betterment of trade and this countries ideals. The fact that they will/can look after the countries subjects whilst visiting or residing in the foreign country is secondary.
Actually, Embassies and High Commissions fall under the remit of the Foreign and Commonwealth Office. UKTI are the main source of betterment of trade between host countries and the UK, which is not part of the FCO, similarly MoD are responsible for defence sales, which again are not part of the FCO. Granted, the High Commissions and Embassies will also step in and the HCs and Ambassadors will be wheeled out whenever a big deal is in the offing, but to say it is their main role is wrong. They are there to protect British interests overseas and to promote foreign policy.