- Mamata Banerjee, Sitaram Yechury, Lalu Yadav are expected to attend
- Congress intends to nominate a consensus candidate for president polls
- The names of Gopalkrishna Gandhi and Meira Kumar have been discussed
Mrs Gandhi personally called up opposition leaders to invite them and most have confirmed they will attend, putting aside regional rivalries. So the Left's Sitaram Yechury will be there as will archrival Mamata Banerjee, who is West Bengal chief minister and Trinamool Congress chief.
Ms Banerjee, back in Delhi on Wednesday, was in the capital last week and had met Mrs Gandhi and Mr Kejriwal separately to discuss candidates for President. Mr Kejriwal has not received an invite because his party has so far not taken part in any joint opposition programme.
Mamata Banerjee will be meeting Prime Minister Narendra Modi today and though officially the agenda is the development of Bengal, the two leaders are expected to discuss the presidential elections. Sources close to Mamata Banerjee say her party's support will depend on who the opposition's candidate is and whether a consensus can emerge around the person's name.
Bihar Chief Minister Nitish Kumar has said he will not be able to attend and will send a representative, but his partner Lalu Yadav has already left for Delhi. Mayawati of the Bahujan Samaj Party will attend or send a representative. DMK too is expected to send a senior leader.
From the Congress, Sonia Gandhi's son and deputy Rahul Gandhi will attend as will former Prime Minister Manmohan Singh and other senior party leaders.
Sources said the opposition is unlikely to decide on a candidate for President just yet. Most of them will also meet after a week in Chennai on May 3, for DMK chief M Karunanidhi's birthday celebrations. They are also expected to wait and watch who the BJP picks as its candidate.
Former Bengal governor and Mahatma Gandhi's grandson Gopalkrishna Gandhi is said to be a forerunner to be the opposition's candidate and is strongly backed by Ms Banerjee. Former Lok Sabha Speaker Meira Kumar's name has also been discussed.
Nitish Kumar had suggested a second term for President Pranab Mukherjee whose term ends in July, but the President has made it clear that he will consider it only of the government nominates him. The ruling BJP has so far not seemed inclined to do that.
Veteran politician Sharad Pawar of the Nationalist Congress Party (NCP) declined Sonia Gandhi's offer to be the opposition's candidate for president, but will be there at her lunch party.
Mr Pawar is believed to have said no because his party is not keen that he contest an election he is likely to lose. The opposition has little chance of winning the Presidential election against the NDA which has over 48.5 per cent support in the electoral college that elects the President and needs only a little support for the 51 per cent required for its candidate to win.
Win or lose, say opposition leaders, they want to make a statement by challenging the BJP. They are also testing ground for an anti-BJP alliance in the 2019 elections when Prime Minister Narendra Modi will seek a second term.