Hiiraan Online

Representatives of more than 50 countries and organisations attended the London meeting, which is co-hosted by Mr Cameron and Somali President Hassan Sheikh Mohamud.

The meeting is aimed at boosting political stability in the impoverished African country, which has had no effective government since 1991. It is also expected to pledge action on rape, which the United Nations (UN) says is "pervasive" in Somalia.

Mr Cameron praised improvements in Somalia’s security in recent months, but warned that huge challenges remained in preventing it from sliding back into abject lawlessness.

"To anyone who says this isn’t a priority or we can’t afford to deal with it, I would say that is what we’ve said in the past and look where it has got us — terrorism and mass migration," he said.

"These challenges are not just issues for Somalia. They matter to Britain — and to the whole international community. Why? Because when young minds are poisoned by radicalism and they go on to export terrorism and extremism, the security of the whole world is at stake."

The UK has raised eyebrows by inviting Kenyan President Uhuru Kenyatta, who faces an international trial for crimes against humanity, to the meeting.

A UK government source said the invitation counted as "essential contact" with Mr Kenyatta, who goes on trial at the International Criminal Court in July.

Downing Street said Kenya played a "vital" role in Somalia, because it has nearly 5,000 troops there and it hosts more Somali refugees than any other nation.

The UN, African Union and International Monetary Fund are among the organisations attending the conference.

Somalia has been battered by conflict since 1991 but a new UN-backed government took power in September, ending more than a decade of transitional rule.

Al-Qaeda-linked al-Shabaab militants were driven out of the Somali capital Mogadishu by African troops in August 2011, but the Islamists have carried out brutal attacks in recent months.

About a dozen people were killed in the city on Sunday when a suicide bomber rammed a car full of explosives into a government convoy carrying officials from Qatar.

Despite the unrest, Somalia appears to be slowly turning a corner, with businesses reporting growth in activity.

The UK last month became the first European Union country to reopen an embassy there since the conflict broke out, while the UN Security Council set up a special mission to Somalia last week that will bring in up to 200 security, human rights, political and financial experts to work with the fledgling government.

Mr Mohamud urged the international community to pour investment into Somalia, saying his government’s progress over the last year had defied sceptics.

"We are here today to begin a four-year process that must begin with considerable investment and support, but which I hope will finish with very little," he told the conference.

"My vision is for a federal Somalia at peace with itself and its neighbours and which poses no threat … a Somalia with a resurgent economy."

Mr Mohamud’s government remains weak, and large parts of Somalia are still carved up between rival militias.

Campaigners Human Rights Watch say rape by soldiers and gunmen is an "enormous problem" in Somalia.

The UK and the United Arab Emirates last month pledged £1m each to help tackle sexual violence.

More than a million Somalis are refugees in surrounding countries and another million are displaced inside their homeland, often living in terrible conditions.