pdesjard

I am due to fly from South Africa to UK, then UK to Russia. I hold dual nationality - British and South African. I intend to enter UK on my British passport. Can I depart the UK using my South African passport en route to Russia? Reason I'm using my SA passport to exit UK is the agreement between South Africa and Russia meaning no visa requirements for south African passport holders entering Russia. But I wondered if UK Border Agency would permit flying from UK to Russia using a South African passport.