LONDON — Rival camps vied to seize momentum on Monday for the final stretch before Britain’s referendum on European Union membership, after the shock killing of a lawmaker halted the campaign.

Politicians will return to parliament, which had been in recess, for a special sitting to pay tribute to Jo Cox, a pro-EU campaigner murdered on a village street last week.

Politicians on both sides of the debate sought to lay out their case to voters with just three days left until the ballot.

"You can change the whole course of European history," wrote pro-Brexit campaigner Boris Johnson in the Daily Telegraph.

"I hope you will vote Leave, and take back control of this great country’s destiny," he implored. "This chance will not come again in our lifetimes, and I pray we do not miss it."

Prime Minister David Cameron called on voters to pick "Remain" in a sometimes heated BBC television appearance on Sunday evening.

"If we do leave we are walking out the door, we are quitting," Cameron urged.

"I don’t think Britain at the end is a quitter. I think we stay and fight.

That is what we should do."

The Leave and Remain sides have battled each other to a stalemate with each on exactly 50 percent support, according to an average of polls calculated by research site What UK Thinks.

The vote on Thursday could see Britain become the first country to leave the 28-member European Union, a prospect that rattled markets last week, when the Leave side appeared to be gaining.

Opposition Labour leader, Jeremy Corbyn, is due to be grilled by a live television audience later on Monday as he makes his case for Remain.

The murder of fellow Labour party politician Cox, who was known for her pro-EU stance and refugee advocacy, caused widespread shock and questions over whether the tone of the campaign had been divisive.— AFP