New Delhi, March 28 -- Congress leader Pramod Tiwari attacked the Bharatiya Janata Party (BJP) after West Bengal Chief Minister Mamata Banerjee was heckled by students during her speech at Kellogg College, London and said that leaders who go abroad should be allowed to express themselved.

"Whatever happened with Mamata Banerjee, her party will speak over that and will give their reaction...but this a very bad tradition started by the BJP. If their (BJP) leaders go abroad, they (BJP) gather people and raise their voices in support...I believe that India's image should not be maligned at the international level...So, whoever goes abroad for a speech or lecture, at that time, the leaders should not be criticised. They should be given a chan...