1.   If they hit a gas pocket while drilling, the resulting blowout can sink the rig.

2.   However, in September the environmentalists admitted that they had been wrong in their original analysis of the dangers involved in sinking the rig at sea.

3.   British Prime Minister John Major defended sinking the rig as the least environmentally damaging solution.

4.   But Shell denies the platform is full of toxic waste and has persistently maintained that sinking the rig represents the most ecologically sound disposal method.

5.   Energy Minister Tim Eggar said in the new year that about a dozen rigs might be sunk at sea.

6.   Shell claims that if the rig were sunk, the sludge inside would remain localized and not pose a widespread environmental hazard.

7.   The company has persistently maintained that sinking the rig represents the most ecologically sound disposal method.