Motorways, temporary Lanes and White Lines

Hi All

Just one to query as I can't find any official on this but does any one authoritatively know what the law states about crossing a solid white line when in a temporary lane situation, ie, when travelling on the hard shoulder that has be set up as a temporary 'left lane' so that work can be done on the outside lane, can I legally cross the solid white line?

Several laws exist to say that I cannot cross it, but I can't find any that definitely say, technically or legally for that matter, that I am legally allowed to cross the line.

Any info and cite of a formal web site would be appreciated.

Cheers

Starb7