Hey
Like has already been said it is a complete 5 year history they require to gain an 'Airside Pass'.
Lets say for exaple, in a typical year, you worked for one company between January and June. You would be required to provide details of your employer so that the I.D Dept. can send out a reference questionaire.
Now, like you said, temping could prove more difficult; so lets imagine, for the rest of the year you worked for a temping agency. More important than the charector reference itself, the employer needs to confirm dates. My guess is that a 'temping agency' would be able to supply this information.
In the U.K, we have also had to get the Inland Revenue to back up these dates by asking them to provide a letter containing all of our employments within the last 5 years. Typicaly if any periods of employment don't appear on the letter, these are cross referenced with another party, of whom you have been known too for a number of years.
To give you an idea I finished my training about 6 weeks ago, and I have just got my pass. After training your sent home on basic pay, but are responsible for chasing your own ref's. (boring and frustraing!!)
I am not an expert, but hope this helps!!
