The twin gatherings reflected the deep divisions in Lebanese society. A huge security operation was mounted by the Lebanese army to keep the two groups of mourners apart. In the end, there were no serious clashes. For that we can be relieved. But there can be no disguising that the delicate balance of the Lebanese constitution remains on the verge of collapse.

Mr Hariri's assassination in 2005, which many suspect the Syrian intelligence services of ordering after it emerged that the former prime minister was preparing to return to office and demand the withdrawal of Syrian troops from the country, has engulfed Lebanon in chaos. Considerable domestic and international pressure after Mr Hariri's death did indeed result in a Syrian military withdrawal, but the so-called "Cedar Revolution" has since stalled.

Pro-Syrian Hezbollah withdrew its ministers from the coalition government en masse in November 2006, creating political deadlock. The office of president has stood vacant since last November. The prime minister, Fouad Siniora, remains in office but wields no real power. The two factions have refused to work with each other in parliament. Hezbollah and its allies have set up a tented village in downtown Beirut, outside government buildings, as part of their campaign to force early parliamentary elections.

The Israeli military assault on Hezbollah in the summer of 2006 failed to unite the parties in the face of a common threat. Nor did the bloody struggle last May, when the Lebanese army confronted a militant Islamist organisation that had established itself in a Palestinian refugee camp near Tripoli.

But most destabilising of all has been the wave of assassinations of anti-Syrian figures. The Lebanese police officer charged with investigating the killings, Captain Wissam Eid, was himself assassinated last month. These deaths have sparked mass demonstrations and violent clashes. The army is holding the line, but if it came to a full-scale trial of strength with Hezbollah's militia, few believe it would prevail.

The search for a political solution to the crisis has been slow and faltering. A national unity government has been proposed, to be headed by the army chief, Michel Suleiman, who is a figure apparently acceptable to both sides. But, as part of any deal, pro-Syrian groups are pushing for a new formula for government which would guarantee them a third of cabinet seats. This would give them an effective veto on all government policies, something the other parties are refusing to accept.

What Lebanon needs is for its political leaders to realise that the present impasse is threatening what the country has achieved since the end of the civil war. What Lebanese politics emphatically does not need is any more manipulation by the Syrian, Iranian, Israeli or United States intelligence services. Lebanon has had quite enough foreign interference. Its leaders must be allowed to chart their own course out of the chaos.