Kolkata, Dec 13 : The West Bengal Government has approached a Division Bench of the Calcutta High Court, challenging an earlier order directing an interim stay on any kind of investigation by Kolkata Police against the BJP legislators accused by ruling Trinamool Congress of insulting the National Anthem within the state Assembly premises. On December 7, the single-judge Bench of Justice Jay Sengupta had stayed any investigation in the matter till January 17. However, on Wednesday, the state government approached the Division Bench of Justice TS Sivagnanam and Justice Hiranmay Bhattacharya and challenged the stay put by Justice Sengupta's Bench. Political observers say that the recent development makes it clear that the matter has become a prestige issue for the ruling Trinamool Congress and they are set to see it through to the end. While putting the interim stay on investigation in the matter Justice Sengupta made some observations on the merits of the case. While questioning the video footage presented by the state government relating to the case and observing that the footage does not substantiate the charges of insulting the National Anthem by the BJP legislators, Justice Sengupta also observed that the National Anthem cannot be used as a political medium. 'It has to be seen whether the National Anthem was sung to pay respect to it or was it used to frame the opponent,' Justice Sengupta observed. The incident occurred on November 29 when Trinamool Congress legislators sporting black shirts and led by Chief Minister Mamata Banerjee, were protesting near the statue of BR Ambedkar within the Assembly premises against the non-release of central funds to the state government for various centrally-sponsored projects. Towards the end of the protest, a group of BJP MLAs led by the Leader of Opposition (LoP) arrived at the Assembly premises. The legislators, including the LoP, were seen shouting "thieves', 'thieves" while pointing at the protesting demonstrations. Later the Chief Minister complained to the Speaker that the BJP legislators were raising derogatory slogans while the ruling party MLAs were singing the National Anthem, deeming it an insult. Later three Trinamool Congress legislators filed a complaint in the matter, following which the police started an investigation in the matter by registering an FIR. /IANS