When Mr Sharif won a huge majority in elections held about two and a half years ago, the opposition was fragmented and demoralised.

The prime minister moved swiftly to consolidate his hold on power. He successfully confronted the other elements in Pakistan's traditional power structure and soon saw the back of a hostile president, a chief justice of the supreme court with whom he couldn't see eye to eye and an army chief who appeared to act independently of the government.

Consolidation of power

Mr Sharif was able to install a family loyalist in the presidency and appointed a chief justice and an army chief who appeared sympathetic to his point of view.

Earlier, he was able to put his two-thirds majority in parliament to good use.

He amended the constitution and took away from the president the right to sack governments and dissolve assemblies - a device which was used against his arch-rival Benazir Bhutto twice and of which he himself was a victim during his first period in power.

Economic difficulties

The first hint of trouble for the prime minister came when Pakistan responded to India's nuclear test explosions by carrying out tests of its own in May last year.

The resultant halt in disbursement of funds from international financial institutions exposed the fragility of the country's economy.

And it also became apparent that Pakistan needed to take some tough economic decisions if the country was to function smoothly.

But critics of the government say that it responded with its now-customary casual attitude and did nothing.

Kashmir a rallying point

Army disgruntled after Kashmir withdrawal

Then, earlier this year, taking advantage of an early thaw, Pakistan-backed forces moved deep into normally snow-bound mountainous regions of Indian-administered Kashmir.

For nearly two months, there was a stand-off between the world's newest nuclear powers.

It raised fears around the world of an all-out war and brought enormous international pressure on Pakistan to withdraw these forces.

Watching the army

Where this withdrawal may have enraged the army, it also served as a rallying point for the disparate opposition groups in the country.

And to add to the discomfiture of the government, the International Monetary Fund (IMF) has now imposed tough conditions for the continued flow of funds to Pakistan.

Small businesses and traders - traditionally seen as political allies of Mr Sharif - are up in arms against the imposition of a 15% general sales tax (GST).

This has given fresh impetus to the forces arrayed against the prime minister.