Dads got a Disco but what is this button?

Chaps my old man just bought a 95/6 N reg disco in Gravesend 103k on the clock in gunmetal grey, apparantly quite nice and 3 owners he hasnt a clue about them and after all my experiances 3 years on disco's he thought it would be a good idea to get one!!!!!! mad fart.
Any way it has cruise control but somwhere there is a button with what looks like a goalpost! on the left side of the steering column, i think it is a motorway sighn, but have no idea what it does, press it and find out hasnt worked so i was hoping someone may be able to enlighten us i cant photo it as we live 80 miles apart.
Thanks

Master switch for the cruise control. The switch symbol should glow when the switch is pressed 'on'.

Unwanted passenger ejector seat. Part no. RTC007

Cheers chaps crikey that was quick, that makes sense cheers he's going on a run tommorow down to dover so he'll try it out. if he gets over 50!!!
cheers DSCOOL for the pm .