He won a landslide election victory with 134 seats in the 217-seat assembly - one of the largest mandates in history.

But the election turnout had been Pakistan's smallest ever, and Mr Sharif failed to last his first term of office in the early 1990s.

Pakistan's army: its former power has been curtailed

The second time round, Mr Sharif's first big move was to increase his power at the expense of the president, by removing the presidential right to sack leaders.

Supported by his large majority, the prime minister has taken on the institutions which wield much of the power in the country - and won.

In 1998, Pakistan's powerful army chief resigned when the military's calls for input in government decisions were ignored - a considerable political victory for Mr Sharif.

And thousands supported the prime minister's proposals to introduce Islamic Sharia law, hoping that this would help restore law and order to violent areas like Karachi.

But a recent move to set up military courts in Karachi to combat crime and terrorism has drawn mixed reactions.

Unique background

Nawaz Sharif was born in Lahore, Pakistan in 1949 to a family that originally migrated from Kashmir, made its fortune in steel before moving into sugar and textiles

Most of Pakistan's political elite has tended to come from the agricultural, rather than industrial sector.

Mr Sharif beat former prime minister Benazir Bhutto in the 1997 election immediately following her dismissal on charges of corruption.

The enmity between the Bhutto and Sharif families goes back over 20 years, when Benazir Bhutto's late father and then Prime Minister, Zulfiqar, nationalised the Sharif steel business as part of his programme of nationalisation.

Nawaz Sharif joined the party of President Zia ul-Haq who overthrew Benazir's father in 1977 and had him hanged in 1979.

President Zia appointed Mr Sharif the provincial finance minister and later chief minister of Punjab during the martial law regime.

In 1993, the two clashed over allegations of corruption - but the incidents only helped establish Nawaz Sharif's populist credentials.

The 'businessman's prime minister'

Mr Sharif is from the conservative Pakistani Muslim League.

At first, he was seen as a member of the establishment, becoming known as the "businessman's prime minister" after introducing a number of deregulatory measures.

Mr Sharif is the most powerful PM in history

He backed lots of pro-business policies - allowing new private banks, removing controls on new industries and exchange transactions and allowing foreign investors to invest in the stock market for the first time.

The moves were welcomed by the business community and many international commentators.

But Mr Sharif's first year back in power disappointed the public after his promises about changing the destiny of Pakistan.

The main indicator still worrying ordinary Pakistanis is the faltering economy.

Nawaz Sharif took gambles to try to raise more money, including lowering many taxes in the hope that more people would pay.

So far, the gambles have not paid off, and a promised campaign against corruption and politics has yielded few results and no major prosecutions.

Nawaz Sharif has become the most powerful leader in Pakistan's history, but he has yet to convince the people that he can use the power to fulfil his promises.