Trinamool Congress chief Mamata Banerjee's impetuous nature is apparently the reason for her being kept out of the Union Cabinet.

A BJP general secretary told rediff.com that Banerjee's persistent behind-the-scenes lobbying for a cabinet berth has found favour with Prime Minister Atal Bihari Vajpayee, especially after the BJP's decisive victory in Gujarat.

However, Lal Kishenchand Advani's followers are adamant on Mamata tendering an unqualified apology to the deputy prime minister for calling him a 'villain' when he reportedly opposed her party's stand during the controversy over bifurcation of the Eastern Railway.

"Nobody can badmouth the deputy prime minister and get away with it," the BJP leader pointed out.

After her verbal assault on the deputy prime minister, the Trinamool chief announced at a press conference in Delhi that her party would stay out of the ruling National Democratic Alliance government till the bifurcation issue was solved to her party's satisfaction.

The Union Cabinet was firm on bifurcation and Mamata was out of the NDA.

This weakened her clout in West Bengal and further helped the resurgent ruling Left Front consolidate its hold on the state.

Trying to retrieve the situation, Mamata reportedly even made an attempt to woo former Trinamool senior leader Ajit Kumar Panja into the party fold.

He had stormed out of the Trinamool after Banerjee gave him a tongue-lashing for reportedly cosying up to BJP leaders in the hope of getting a central ministerial berth. Right now, he is considered an independent member of the Lok Sabha.

On Monday, as part of her own efforts to cosy up to the BJP leadership, Mamata shared the dais with NDA leaders at a rally in Kolkata for the first time in two years.

"Eastern Railway's bifurcation has been approved by the Union cabinet. Yet, Banerjee wants to return to the Union Cabinet. You can draw your own conclusions from this," the BJP general secretary said.

However, NDA convener George Fernandes, who was present at the Brigade Parade Ground rally, was non-committal on Mamata's induction into the Union Cabinet.

More reports from West Bengal