Dubbing it as a 'national resource', Prime Minister Manmohan Singh is believed to have favoured return of spectrum from any telecom operator who is found having airwaves in excess of the contractual obligation.A suggestion to this effect is understood to have been given by Singh when Communication Minister A Raja met him on Friday night (November 30).The CDMA operators led by Reliance Communications and GSM service providers led by Bharti Airtel are slugging out in public on the issue of allocation of spectrum to mobile firms.While no official comment could be obtained on the meeting between Raja and Singh, sources indicated the Prime Minister also disfavoured suggestion of referring the issue of spectrum allocation to an empowered group of ministers as suggested by some of his Cabinet colleagues.According to DoT sources, top GSM operators have got beyond the contracted obligation of 6.2 MHz of frequency (in some cases the contracted quantity is only 4.4 MHz).In Parliament also, members belonging to various political parties especially Samajwadi Party leader Amar Singh has raised the issue of surrender of surplus spectrum.While Anil Ambani, in a series of letter to the Prime Minister, accused GSM operators of hoarding spectrum, Bharti Airtel chairman Sunil Mittal refuted this, saying the CDMA operator should put his mathematics in order.The government has also constituted a panel with representatives from the Department of Telecom (DoT) and operators to review the recommendations of Telecom Engineering Centre which had suggested that the subscriber base be increased by 2-15 times to become eligible for additional frequency.