Prime Minister Gordon Brown has made a top secret trip to Iraq to deliver a Christmas message to British troops.Mr Brown flew to Basra under cover of darkness and told a group of servicemen and women control of the province will be handed back to the Iraqi government in two weeks.Britain's remaining 4,500 troops are to focus on training local forces, paving the way for the withdrawal of 2,000 British soldiers in the spring.Mr Brown told troops: "The great venture that started with all the difficulties we face, that cost causalities, means we have managed now to get Iraq into a far better position."Not that violence has ended but we are able to move to provincial Iraqi control and that's thanks to everything you have achieved."I know many of you will not be home for Christmas but I do appreciate the spirit of service that means you are serving here the national interest at Christmas time."The Prime Minister earlier delivered a tough message to the captors of five Britons being held hostage in Iraq, demanding their "immediate release" and warning that the "unjustified" action would not change the Government's policy."We will do everything in our power to secure our objective, which is the immediate release of the hostages," he said."The taking of hostages is completely unjustified, wholly unacceptable and we are making it clear they will not change our policy in any way."© Independent Television News Limited 2007. All rights reserved.