As British troops yesterday transferred control of Basra to the Iraqi authorities four-and-a-half years after the invasion, the big question on the streets of the city and elsewhere is whether Iraqi security forces are ready to take on the responsibility for policing their own streets.

Britain’s Prime Minister Gordon Brown obviously thinks so. But a closer look at reality shows that Britain’s handover of Basra province will have a limited effect on security in Iraq’s biggest oil region because rival warlords and local officials have been wielding real power in the area, especially since the 2005 elections, when southern Iraq came under the control of Shiite parties and their allied militias.

The relative security of Basra owes more to the dominance of militias and criminal gangs, who have achieved a fragile balance in the city, than to the success of British forces. In short, British troops are leaving, not because their job of ensuring security is done but because it isn’t. This view is shared, according to an opinion poll, by more than 85 percent of the residents of Basra who believe British troops have had a negative effect on the Iraqi province since 2003. The poll of nearly 1,000 people also suggests that 56 percent believe British presence has increased the overall level of militia violence. Just as significant, two-thirds think security will improve after the British return control of the province to Iraqi forces. In fact, there never was any real British control of Basra. What happened yesterday was just a nominal transfer of authority to the central government and Iraqi forces. After the deaths of more than 170 servicemen and women since 2003, Britain is now simply cutting its losses. Nevertheless, the handover will mark a significant milestone toward Britain’s final withdrawal from southern Iraq. Basra is the ninth of Iraq’s 18 provinces to resume responsibility for its own security. It is unsure whether there will be an even larger security vacuum than there already is. The US lacks the troops needed to guarantee security in northern and central Iraq, much less face new crises elsewhere in the country. With few troops in the south, the Americans have little choice but to hope the Iraqis can handle any surge in violence or that political deals among the power brokers in Basra can prevent a blowup, Even though Britain had long seen its influence over events in southern Iraq diminishing, the mere presence of substantial British forces offered assurances the situation in the strategic area would not spiral out of control. British officials will retain the ability to help Iraqi troops quickly if widespread violence erupts, but by the spring, they will reduce the number of troops in the country from 4,500 to 2,000.

The British have never sought to maintain the same level of control as the Americans did over Iraq after the 2003 invasion. But since the invasion, British forces have had a role to play in Iraq and that role was supposedly more than simply protecting themselves.