Have Frank and Joe ever worked with MI6?

[Hardy Boys UB Fan]

Have the Hardys ever worked with MI6 or MI5?

[MacGyver]

If you mean, "Have Frank and Joe Hardy ever met James Bond?", then, yes.
According to The Hardy Boys Wiki, James Bond is mentioned in Death and Diamonds and Haunted (both titles within The Hardy Boys Undercover Brothers universe). And The Hardys worked with someone who was not outright identified as such, but definitely was meant as a cameo appearance from James Bond in one of the graphic novels.

[P. Walker]

didnt they meet up with an agent from British Intelligence after the hi-jacking in Dead on Target? I forget the guys name

[SkyWarp]

didnt they meet up with an agent from British Intelligence after the hi-jacking in Dead on Target? I forget the guys name

http://www.hardyboyscasefiles.com/search.php?q=british+intelligence

Why, yes, BI is mentioned, but nothing about MI6 specifically in DoT.

[tomswift2002]

In "Assault On The Tower" the boys work with a British secret agent (who is played by Patrick MacNee) and is meant to be Steed from "The Avengers", but because of copyright issues with the character, MacNee's character could not be identified as Steed.

[MacGyver]

That's right- forgot about that one. So we have an encounter with James Bond in the comic books and an encounter with Steed from The Avengers on the '70s TV show. And British Intelligence is mentioned in Dead on Target, though I feel fairly certain The Hardy Boys have worked with British operatives in other books as well.

[MacGyver]

If you mean, "Have Frank and Joe Hardy ever met James Bond?", then, yes. 
According to The Hardy Boys Wiki, James Bond is mentioned in Death and Diamonds and Haunted (both titles within The Hardy Boys Undercover Brothers universe). And The Hardys worked with someone who was not outright identified as such, but definitely was meant as a cameo appearance from James Bond in one of the graphic novels.

This nice review of the graphic novel in question reminded me that the Hardy Boys met James Bond in #3 Mad House.