Towering bonfires are being lit in loyalist areas across Northern Ireland to usher in the main date in the Protestant loyal order parading season.

A number of the pyres, mainly constructed by stacking wooden pallets, were set alight late on Monday evening with the rest to be ignited at midnight.

Police said a number of complaints had been received about flags, effigies and election posters being placed on bonfires and officers would review evidence to establish if offences had been committed.

The build-up to the “Eleventh Night” celebrations was overshadowed by the death of a bonfire builder in Co Antrim on Saturday night.

John Steele, a window cleaner who was aged in his mid-30s, was killed when he fell from a bonfire in Larne that stood more than 50 feet tall.

A vigil was held at the site of the fire in the Antiville estate on Sunday night.

The bonfire was dismantled earlier in the day and the remnants were lit during the memorial event for Mr Steele.

A flute band played at the vigil while a minute’s silence was also held. Wreaths were laid close to the scene of the fatality.

Mid and East Antrim Council, which owns the land where the fire was built, announced on Monday that it was launching an investigation into the fatal fall.

More than 250 bonfires have been constructed in loyalist neighbourhoods across Northern Ireland.

The fires are traditionally ignited on the eve of the “Twelfth of July” – a day when members of Protestant loyal orders parade to commemorate the Battle of Boyne in 1690.

The battle, which unfolded at the Boyne river north of Dublin, saw Protestant King William of Orange defeat Catholic King James II to secure a Protestant line of succession to the British Crown.

Most of the bonfires pass off every year without incident, but a number continue to be the source of controversy.

The SDLP’s Paul Doherty condemned those behind putting his election poster on a bonfire in west Belfast.

He said: “While I respect everyone’s right to celebrate their culture in their own way, we regularly see posters of nationalist representatives and hate speech on these bonfires and we need leaders in the unionist community to call it out and put a stop to it once and for all.”

“I have also heard concerns about the building of this bonfire so close to the local community centre and would ask those taking part to ensure that this bonfire passes off as safely as possible with no damage caused to the local community or surrounding areas.”

People Before Profit MLA Gerry Carroll said his election posters were also placed on the bonfire.

He said: “Unfortunately there has been a deafening silence from many unionist politicians in the face of this kind of sectarian intimidation.

“It is time for leadership, and to demand an end to this provocation.”

Alliance Party MLA Stewart Dickson tweeted: “Saddened to see once again Alliance and other party election posters together with flags ranging from the EU to the Vatican and the Republic of Ireland on bonfires in East Antrim.”

The PSNI tweeted: “The Police Service has received a number of complaints relating to flags, effigies, election posters and other emblems being placed on bonfires.

“We are gathering evidence in respect of these complaints and will review to establish whether offences have been committed.”

Around a dozen fires are considered potentially problematic by police.

One potential flashpoint this year is the site of a fire at Adam Street in the loyalist Tigers Bay area of north Belfast.

Nationalist residents from the nearby New Lodge estate have previously claimed the fire is located too close to the interface between the two communities – something the bonfire builders have denied.

Prior to the accident in Antiville, Larne had been making headlines for another bonfire in the town.

Bonfire builders in the nearby Craigyhill estate are attempting to break a world record for the tallest bonfire – a record which currently stands at 198 feet.

On Sunday, the builders in Craigyhill vowed to continue with their record bid in tribute to Mr Steele’s memory.

On Monday, the wooden tower was measured using lasers and a drone, and found to be 202.3ft high.

The Police Service of Northern Ireland (PSNI) plan on the Twelfth being their busiest and most resource intensive day of their year, with the Eleventh Night being second.

There will be 2,500 police officers on duty on the Twelfth, which is around a third of the strength of the PSNI.

On July 12, there will be 573 loyal order parades. Of these, 33 follow routes that are deemed to be sensitive.