In a last bid to break the Singur deadlock, Buddhadeb Bhattacharya has proposed to offer an extra 50 per cent as cash compensation for land at Singur. But Mamata Banerjee still wants 400 acres back. In a meeting called at short notice in Kolkata last evening, Bhattacharya offered a new financial package but Mamata did not approve. So the dark cloud over the Tata's Nano project at Singur refuses to be dispelled.