I was asked to go into the back of a trailer while the forkift truck loads the trailer ,inches away from me… 
No thanks are these people real. 
hse.gov.uk/workplacetranspor … oading.htm
They really need to shape up,and employ somebody with a brain.
Your post is ambiguous at best.
Was the trailer being loaded by a fork lift truck and the pallets needed pallet trucking to the front?
Were you on a bay and being loaded by a Power pallet truck and asked to go into the trailer at that point to check something?
The HSE rules are quite clear in saying only the people involved in the loading/unloading process should be present, being the driver of the vehicle in the majority of cases you will be involved in that process to some extent.
So long as both parties have clearly formed a plan on how to load the vehicle safely then I see no issue here, if the fork lift driver is being too gung ho then ask them to stop/wait until you are ready for the next pallet, if they ignore then stop and report it the goods in/out office and state you are not prepared to be put at risk by the fork lift driver.
This is unless any site specific rules prohibit such activities taking place as then you would follow the sites H&S rules.
Sofidel in Leicester want you in the back of the trailer while forklift driver loads it …No Bloody chance
Furthermore i no understand ,all the employee,s NO SPEAK… 
Say no more.
Matter of time before a nasty accident happens here…
To right ! A confined space with a Tnat on a fork lift no thanks
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