One year on from the execution of brutal dictator Saddam Hussein, the future looks bright for the Iraqi people. There is a renewed sense of confidence in a nation that just six months ago teetered on the brink of disaster.

The surge of 20,000 additional US troops has been an unqualified success, dramatically reducing sectarian violence in the Sunni heartlands, driving out thousands of al-Qaida terrorists, and averting
the prospect of a full-blown civil war.

The number of insurgent attacks now stands at its lowest level since January 2006, with IED (Improvised Explosive Device) bombings down by 60 per cent, and civilian deaths plummeting.

Casualties among Iraqi security forces have also declined significantly, and the Iraqi army has now taken over responsibility for security in nine of Iraq's 18 provinces.

In contrast, the foreign jihadists who have wreaked so much havoc in the country in the past four years are taking a heavy hit, with 40 al-Qaida leaders killed or captured in October alone.

The economy is also looking up, with Iraqi crude oil production exceeding pre-war output for the first time.

According to US Treasury statistics, there are now more than 40,000 registered businesses in Iraq, an increase of 500 per cent since the days of the Saddam regime.

As a mark of economic progress, eight million Iraqis (a third of the population) now carry cell phones, compared to virtually none before the 2003 invasion.

There can be no denying that, in areas where the United States has flexed its military muscle, immense progress has been made in much of the country in the second half of 2007.

The same cannot be said, however, of parts of southern Iraq where Gordon Brown's policy of drawing down Britain's troop presence is allowing neighbouring Iran to increasingly exert control.

There is a sharp contrast between Washington's proactive, strong commitment to defeating the terrorist threat in central Iraq, and London's almost complete withdrawal from a military role in the south.

The decision to reduce Britain's troop strength from 4,500 to 2,500 service personnel in the spring sends all the wrong signals at a time when Iran is becoming increasingly belligerent and aggressive.

It also projects an image of weakness, and as Colonel Tim Collins, a key UK commander of the 2003 invasion, noted, the retreat from Basra "badly damaged" Britain's military reputation.

Basra, Iraq's second largest city and its only port, is in the grip of Iranian-backed Shia militias, brutally enforcing their brand of Sharia law, including the widespread oppression and intimidation of women.

The Prime Minister has rightly made the British campaign against the Taliban in southern Afghanistan a top military priority, with more than 7,000 troops fighting in Helmand Province.

However, it should not be at the expense of maintaining a robust military presence in Iraq. Both Iraq and Afghanistan are vital theatres of operation as part of a longer-term global war that Britain, the United States and the West are waging against Islamist terrorists and rogue regimes.

It makes little strategic sense for Britain to strengthen one front while weakening the other. The UK must be able to wage war effectively on two fronts simultaneously, a capability that has to be matched by a significant increase in defence spending.

The Brown government's frail approach in Iraq is already causing strains in the Anglo-American Special Relationship, and there is growing talk in Washington of mounting pressure on US forces to cover the impending British withdrawal.

The White House is preparing for the possibility that all British troops will be out of Iraq by the end of next year.

In that scenario, the United States will need to divert several thousand soldiers from counter-terror operations in central
Iraq to shore up the border with Iran, protect the vital supply routes from Kuwait to Baghdad and combat Iranian proxy militias.

It is not too late though for Brown to reverse course. With the success of US military operations against al-Qaida, and a marked decline in Sunni-Shia violence, the tide has clearly turned in Iraq.

At last this war-torn country, which has seen untold suffering and human misery for decades, is beginning to exorcise the ghost of Saddam and his brutal regime.

It is vital that these advances are not undermined by the spectre of an Iranian-dominated south, and the United States and Great Britain must remain united in heading off the ambitions of Tehran.

Nearly 4,000 Allied troops have been killed in Iraq since 2003, and they laid down their lives for Iraqis to live in freedom. It is important that their sacrifice be honoured with a commitment to ensuring that an Islamic tyranny does not take root.

This is a time for strength and unity in the Coalition, and it is important that Britain play its part in ensuring that a long-term victory is secured in Iraq.

Nile Gardiner is the director of the Margaret Thatcher Center for Freedom.