Thrissur: Prior to the UDF's official announcement of the Lok Sabha candidates, election campaign has begun for Congress leader TN Prathapan, who is likely to be fielded in Thrissur constituency. Graffiti painting for Prathapan's election is very much visible in the constituency, even before the official announcement of candidates. It is said that INC President Rahul Gandhi, who was in the city to inaugurate the fishermen parliament held the other day, has approved the candidature of Prathapan, sources report.