Counting is under way in West Tyrone in a by-election triggered when the last MP quit amid claims he mocked victims of the Troubles.

Sinn Féin's Barry McElduff resigned in January, ten days after controversy flared when he posted a video of himself with a Kingsmill-branded loaf of bread on his head on the anniversary of the notorious Kingsmill massacre.

He insisted the video was not an intentional reference to the 1976 sectarian murders of ten Protestant workmen by republican paramilitaries near the Co Armagh village of Kingsmill, but he acknowledged it had caused hurt and offence to victims' families.

Five candidates are contesting the by-election.

Sinn Féin's Órfhlaith Begley is defending a 10,000-plus majority in a seat where the party took just over 50% of votes cast in last year's general election.

It would be a shock if the abstentionist 26-year-old solicitor, a political newcomer, did not win a seat the party has held for 17 years.

Thomas Buchanan is contesting the seat for the DUP.

The Assembly member - who is the only candidate not aged in his 20s - managed just over half the number of votes notched by Sinn Féin when he ran in last year's general election.

Assembly member and law graduate Daniel McCrossan, 29, is running for the SDLP, while local councillor Chris Smyth is representing the Ulster Unionists.

Stephen Donnelly is the Alliance Party's candidate.

Given the circumstances around Mr McElduff's departure, issues affecting victims of the Troubles have been a key feature of what has been a relatively low-key campaign.

Kevin Skelton, whose wife was killed in the 1998 Omagh bomb, put himself forward as a potential victims' unity candidate, asking the other parties to unify behind him a bid to defeat Sinn Féin.

He failed to secure the necessary cross-party support and did not end up putting his name on the ballot.

Unsurprisingly Brexit has also featured on the campaign trail in a constituency whose western boundary runs along the Irish border.

The referendum campaign on the Eighth Amendment has undoubtedly also had an impact on the dynamic of the by-election debate north of the border.

The candidates' position on the emotive issue has been subjected to greater scrutiny than they might have expected.

Meanwhile, the PSNI has arrested a man in connection with an incident at a polling station in Greencastle, Co Tyrone.

Police say the man was detained on suspicion of possession of a firearm with intent to cause fear or alarm and has been taken into custody for questioning.

An electronic device has been seized from a polling agent at a Strabane polling station this morning.

It is illegal for a mobile phone or electronic device to be taken into a polling station.