Image copyright Reuters Image caption Maryam Nawaz has been campaigning hard ahead of Sunday's by-election

"The lion is here!" shout a jubilant crowd of female supporters of Pakistan's ruling PML-N party.

The "lion" is normally the former Prime Minister Nawaz Sharif, but on this occasion it's his daughter Maryam Nawaz.

Maryam Nawaz does not hold political office, but is one of the most high-profile figures in Pakistan.

She has taken centre stage in the lead-up to Sunday's by-election in her father's former seat, constituency NA-120, in the family's hometown of Lahore.

Her mother, Kulsoom Nawaz, is the party candidate, but she is recovering from cancer treatment in the UK. Maryam Nawaz has led the campaign on her behalf, addressing crowds of thousands of supporters, who have adorned her with rose petals.

The seat was left vacant after her father was disqualified by a Supreme Court panel which ruled he had not been "honest" during an inquiry into corruption allegations. Mr Sharif has always denied any wrongdoing but on Friday the Supreme Court dismissed petitions seeking a review of that decision.

Image copyright Reuters Image caption The by-election is being seen as a referendum on Nawaz Sharif's removal from power

During the by-election campaign Maryam Nawaz has sought to portray the vote as the "people's verdict" on her father's disqualification.

"Does this country want democracy? Or conspiracy?" she asks a gathering of supporters.

Speaking to the BBC, Maryam Nawaz describes the corruption allegations as a "targeted attack" on Nawaz Sharif.

Neither Maryam nor her father have explicitly said who is behind the conspiracy, but it's understood to imply the involvement of Pakistan's powerful military establishment which has clashed with Nawaz Sharif's civilian administration in the past.

Maryam Nawaz tells the BBC her father was punished for standing "for civilian supremacy".

But she says her father's disqualification has "galvanised his supporters" and that public sentiment is "very positive".

Image copyright Getty Images Image caption Nawaz Sharif maintains he has done nothing wrong, following the Panama Papers-linked probe

Portraying the by-election as a kind of referendum on the disqualification of Nawaz Sharif has its dangers for the party, however.

In the 2013 election in the constituency, the PML-N received a majority of nearly 40,000 votes ahead of their closest rivals from the PTI party, led by Imran Khan.

Polls predict a PML-N victory again now, but it's not clear whether their margin will increase or decrease. Fewer votes for the PML-N would allow political opponents to claim that even on the Sharif family's home turf the corruption allegations are having an effect.

Dr Yasmin Rashid, the PTI candidate in NA-120, says she's facing an uphill battle fighting against an incumbent party with greater access to local resources, but claims voters believe Maryam Nawaz is "just as guilty as her father" when it comes to corruption allegations.

PTI supporters say the Sharif family statements about a conspiracy are undermining political accountability.

Maryam Nawaz, though, dismisses the corruption allegations against her and her father as "farce".

Image copyright Reuters Image caption The corruption probe led to anti-Sharif protests in several cities

The election is being contested by all the major parties as well as two new Islamist opposition parties.

One, Tehreek Labaik Ya Rasool Allah, consists of supporters of Mumtaz Qadri - a cult figure executed for murdering a high-profile politician who was trying to reform Pakistani blasphemy laws.

The other, Milli Muslim League, is linked to Hafiz Saeed, alleged by the US and India to be the mastermind of the 2008 Mumbai attacks (which he denies) and thought to have close links to the Pakistani intelligence services.

Neither party has a realistic prospect of winning, but both are likely to primarily draw supporters from the religious base of the PML-N.

Who are the new Islamist parties?

Speaking to supporters of Tehreek Labaik Ya Rasool Allah at a roadside rally, most used to vote for the PML-N. But they stopped supporting the party after the execution of Mumtaz Qadri, carried out whilst Nawaz Sharif was in power.

They told me they were also alienated by what they saw as the PML-N's increasing liberalism, exemplified by Maryam Nawaz. "That's what liberalism is," says one. "Women going around acting like men."

The Milli Muslim League has not yet been allowed to formally register as a political party, so their candidate has to run as an independent. But their posters are across the city, many featuring the picture of Hafiz Saeed.

Their information secretary, Tabish Qayyum, says that previously the Jamaat-ud-Dawa organisation with which they are linked used to encourage supporters to vote for the PML-N as the most "right-wing" of the mainstream parties, but they had been angered by Nawaz Sharif's overtures to India and his perceived lack of support for the Kashmir cause.

One view is that such parties can help encourage radicals to move away from violence to politics. The other is that they will make progressive reform harder to implement.

Maryam Nawaz says she is not concerned about the political impact of the new parties but about "the kind of resources they have. The kind of manpower they have."

The suggestion - again in coded language - seems to be that these new parties are part of the "conspiracy" against the PML-N.

She told the BBC: "They're not there for the elections for themselves - they're there for other reasons."

The military has repeatedly denied any political interference, and both new parties dismiss the insinuation.

Image copyright Reuters Image caption Maryam Nawaz is seen as her father's political heir

The result of this by-election will provide some insight into what could happen in Pakistan's 2018 general election. It could also play a role in determining Maryam Nawaz's future political career.

She insists that she doesn't know "what the future holds" and that she is "very happy working as a PML-N worker" but she is credited with having pushed forward a number of liberal policies in the party, and has long been seen as her father's political heir.

Asked if Pakistan needed to move away from dynastic politics, Maryam Nawaz responds firmly that "public endorsement" is earned not inherited.

The result of Sunday's election will give some indication as to how much public support Maryam Nawaz and her family still command.