Simon Cowell Security Asleep at the Wheel ... When Burglars Struck

12/7/2015 7:34 AM PST

Simon Cowell's in the market for new dogs, and maybe a bodyguard too ... after burglars busted into his mansion while he slept.

Simon spoke for the first time about the Friday break-in and said his first instinct was to check on his son -- “Lauren [Silverman] was woken up with me and we checked on Eric. That was the first thing we did, to make sure he was OK."

Simon, his gf and their son were all home when the crooks hit their London mansion. Simon told The Sun his bodyguard was sleeping during the incident, and added ... "We have the worst guard dogs in the world."

The burglars made off with jewelry and cash ... reportedly in the hundreds of thousands. Simon did praise the security guard, who chased down one of the suspects, and retrieved Cowell's passport. However, he said heads will roll on his security team, if he's being honest.