Radio Polonia reports that the news broke in the midst of preparations for the Archbishop's inauguration ceremony.
Announcing his decision at the service with tears in his eyes, the Archbishop said he had reached the decision after much reflection, the BBC added.
The decision was reportedly a result of negotiations at the Vatican level, the Polish radio station said, citing a source who said that Pope Benedict personally suggested that Archbishop Wielgus step down after finding out that the Archbhishop had not revealed the whole truth in his recent statements to the Vatican about his past collaboration with Poland's communist regime.
Instead of the scheduled inauguration ceremony, a thanksgiving Mass for the work of the previous archbishop metropolitan of Warsaw, Jozef Glemp, took place in the Warsaw Cathedral.
The Polish weekly Gazeta Polska had published allegations before Christmas that then Fr Stanislaw Wielgus had willingly collaborated with communist era secret services for more than 20 years and had continued his collaboration even after the brutal murder of several priests.
Archbishop Wielgus initially denied the allegations. However, after the publication of a series of documents implicating him, he finally admitted his collaboration although he continued to claim that no one had suffered as a result.
According to Radio Polonia, journalists from the weekly WPROST have found that Jozef Kowalczyk, Apostolic nuncio to Poland, was aware of Archbishop Wielgus' problematic past as early as two months ago but may have failed to inform Pope Benedict.
According to a statement issued yesterday by the Vatican representative in Warsaw, the Pope had asked the outgoing archbishop of Warsaw, Cardinal Jozef Glemp, to continue in that post "until further decisions have been taken concerning the archdiocese."
In a homily delivered at yesterday's Mass, Cardinal Glemp defended Archbishop Wielgus and questioned the validity of the documents proven to be true by two independent commissions of historians, one of which was the Church's official historical committee.
Vatican spokesman Federico Lombardi later suggested that the revelations about Wielgus' past may have been leaked by former communists as revenge for the Church's role in their fall from power.
Polish archbishop quits amid row (BBC News, 7/1/07)
Archbishop Wielgus has stepped down (Radio Polonia, 7/1/07)
Full statement of the Vatican's mission in Poland (EITB, 7/1/07)
Vatican fingers former Polish communists in archbishop row (The News, Pakistan, 8/1/07)
‘I did harm to the Church’ says Wielgus (Radio Polonia, 5/1/07)
Even more allegations against Archbishop Wielgus (Radio Polonia, 4/1/07)
LINKS (not necessarily endorsed by Church Resources)
Profile: Stanislaw Wielgus (BBC News)
Archbishop Stanislaw Wielgus (Catholic-Hierarchy)
Archdiocese of Warsaw (Polish)
Archbishop Stanislaw Wielgus (Wikipedia, Polish)
Polish Cardinal says sorry over "super spy" slur (CathNews, 15/11/06)
Polish spies in John Paul II assassination attempt (CathNews, 13/10/06)
Cardinal claims Vatican priests spied on John Paul II (CathNews, 6/9/06)
8 Jan 2007