Hours after Union Minister Arun Jaitley upbraided her in his blog, Chief Minister Mamata Banerjee and her aides took the Centre head on. While party MP Derek O'Brien launched a no-holds-barred attack on the BJP and the National Security Adviser Ajit Doval, his chief was riled enough to use unparliamentary language at a meeting of party workers, calling an unnamed BJP leader by a four-letter word.