Quote: PTB "It would have to be a train from Twickenham to Clapham rather than a tube, but yes, that would be the most sensible option.
It is madness at the train station, but South West Trains are very experienced at doing this and they put on a lot of extra (and longer) trains, which will work in your favour.
Provided you leave Twickenham then you should easily make Gatwick for nine.'"
Great thanks a million. Always did get the tube and train mixed up!