George Galloway will attempt to unseat another Labour MP in the next general election.
The Respect MP announced plans to stand against transport minister Jim Fitzpatrick in Poplar and Limehouse.
Speaking on his Talksport radio show, Mr Galloway said: "It's going to be a battle of the Scots in the East End of London.
"Me standing in the tradition of Keir Hardie, him standing in the tradition of Ramsay MacDonald, the betrayer of everything Labour stands for.
"It's going to be a very interesting contest."
Mr Fitzpatrick downplayed Mr Galloway's chances of success.
He said yesterday's local election in Respect's "heartland" of Shadwell had seen a 6.5 per cent swing from Respect to Labour.
Mr Fitzpatrick told politics.co.uk: "Politics in Tower Hamlets are between Labour and Respect, cohesion versus division, delivery versus oppositionalism."
Mr Galloway had been expected to abandon Westminster politics at the next election.
However, he said his unceremonious eviction from the Commons had encouraged him to stand for another parliamentary term.
Mr Galloway said: "Having been suspended from the House of Commons by Mr Speaker [Michael] Martin entirely unjustly and in an entirely unfair and unnecessary way, I have decided I definitely am going to stand again."
At one point Mr Galloway was widely thought to be preparing a challenge to Jack Straw in Blackburn.
The Respect MP decided, however, to remain in London's East End and turn his attention to his neighbouring constituency.
Mr Galloway waged a controversial campaign against Labour MP Oona King to take Bethnal Green and Bow in the 2005 general election.
Like Ms King, Mr Fitzpatrick supported the war in Iraq and this is expected to feature heavily in the forthcoming election campaign.
Mr Fitzpatrick currently holds a majority of more than 7,000, although he saw a 20 per cent decline in votes between 2001 and 2005.
The transport minister voted for trident renewal, extending detention without trial, ID cards and university top-up fees.
A Respect spokesman told politics.co.uk the party had not yet lined up a replacement candidate to contest Bethnal Green and Bow and were waiting on Gordon Brown to announce his election timetable.