Sixty-four-year-old Bilari MLA Haji Irfan was on his way to attend the wedding of the son of senior Uttar Pradesh Cabinet minister Shivpal Singh Yadav at Saifai in Etawah district when the mishap occurred in the Mujaria area, police said here.
Five persons were also injured as the vehicle overturned and fell into a ditch near Kachla village.
While the legislator died as he was being taken to Bareilly for treatment, SP leader KP Singh and driver Farzad Ali were killed on the spot, they said.
Additional Superintendent of Police, Bareilly, Sameer Saurabh said the injured have been hospitalised in Badaun.
A first-time MLA, Irfan is survived by his wife, four sons and two daughters.