|Jaroslaw said he would continue his brother Lech's, right, policies if elected president [EPA]
Jaroslaw Kaczynski, the twin brother of Poland's former president, who was killed in a plane crash in Russia on April 10, confirmed widely held expectations when he announced that he would run in a snap election to replace his late sibling.
Kaczynski, 60, said he would seek to build on the conservative legacy of Lech Kaczynski if he was victorious in the June 20 poll.
The former prime minister has betrayed little emotion and shied away from political announcements since the disaster that killed 96 people, including first lady Maria Kaczynska and dozens of close political allies.
Experts said that the death of a twin, always deeply traumatic, was made even harder by the deep personal and political bonds that linked the unmarried Jaroslaw with his brother.
Adding to the emotional burden, the twins' mother Jadwiga, 84, with whom Jaroslaw lived until recently, has been in hospital since March in critical condition.
Jaroslaw, the elder twin by 45 minutes, and Lech were child stars, appearing together in a 1962 Polish film titled The Two Who Stole The Moon about a pair of scheming youngsters.
They went to the same high school in Warsaw, the Polish capital, and both earned doctorates in law at university.
As activists in the communist-era Solidarity opposition, they were close to Lech Walesa, its charismatic leader, and helped to topple the government in 1989.
But the twins fell out with Walesa after he became post-war Poland's first democratic president in 1990.
Lech carved out a career in the national audit office, but Jaroslaw spent a decade in the political wilderness.
But in 2001 he emerged as a controversial politician after the twins forged the Law and Justice (PiS) party in an attempt to unite Poland's fractious right-wing scene.
The party the twins founded is conservative on social and moral issues but left-leaning on the economy, favouring more state spending and opposing privatisation.
The PiS is sceptical about further European integration and opposes Poland's early adoption of the euro.
Lech became mayor of Warsaw in 2002 and was then elected president of Poland in 2005 after a tough, mudslinging campaign against Donald Tusk, the country's current prime minister, masterminded by Jaroslaw.
The two found themselves briefly with all the levers of power after Jaroslaw became prime minister in July 2006.
| Lech Walesa said Jaroslaw, left, was the brains behind Lech's, right, actions [EPA]
The twins' hard-hitting double act ruffled feathers in the European Union as they sparred with the 27-nation bloc's heavyweights, most notably Germany.
While their conservative, nationalist vision rallied many in deeply Catholic Poland, notably in small towns and the countryside, it alienated many urban and younger voters.
Jaroslaw's rocky three-party coalition with a far-right party and a populist movement unravelled in 2007.
He lost office in a snap election in November that year which was won by Tusk.
Since then, Jaroslaw has become the bugbear of Tusk's Civic Platform party and the fellow-opposition Democratic Left Alliance.
As identical twins, it was nearly impossible to tell the diminutive, stocky Kaczynskis apart.
But most, including their mother, agreed that Jaroslaw was the political mastermind of the pair.
"Jaroslaw will always be the one with the best strategies," she said.
Walesa, not known for pulling his punches, once had harsher words about the twins, saying: "Jaroslaw was the brains and Lech did whatever his brother decided".