The Congress party is unlikely to attend the special midnight function in Parliament on June 30 to roll-out the Goods and Services Tax (GST), party sources said.They said Congress President Sonia Gandhi deliberated on the issue with former Prime Minister Manmohan Singh, senior leaders, including Ghulam Nabi Azad, Mallikarjun Kharge, Ahmed Patel and Jairam Ramesh on Thursday to take a final decision.The Trinamool Congress has already decided not to attend the midnight programme as a mark of protest against the "unnecessary disastrous hurry" to roll out the pan-India tax regime.Sources said the Trinamool Congress is keen that the Congress too adopt the same course.According to sources, a section of the Congress is in favour of attending the function as GST is the party's brainchild, but another section feels the party should abstain to protest the way the tax regime is being implemented.The GST will be launched at a function in the Central Hall of Parliament on June 30.