Hi there, there is a regular train service from St. Pancras (up to 4 trains an hour) and they take 30 minutes to get to Luton Airport Parkway, from there I believe you have to take a shuttle service to the airport terminal.
Alternatively, and as a cheaper option, you can take a coach (National Express) from the central London Victoria Coach Terminal to the airport terminal. There are 3 services an hour, but the journey takes around 70 minutes.
Last Cruise: P&O Adonia June 2014
Next Cruise: Azamara Journey August 2014
Golden, Grand(2), Caribbean, Sea(4+1 aborted)
Adonia(4+2), Arcadia, Artemis(2), Aurora(5), Azura(2), Oceana(3), Oriana(11), Ventura(2), Victoria(5)
QM2(2), QE2(9), QV(5), QE, Caronia(2), Minerva II, Fred.Olsen(8), NCL Jade, =X= Eclipse, HAL Ryndam