undetected

However, it said a security assessment found that since 2019 Broadcasting House had been targeted by 119 protests and that reopening the reception areas would leave the building susceptible to protesters entering undetected.

"The after take-off checklist is designed to trap the latter omission, but the incorrect switch selection went undetected by the crew," the report states.

The terrain is mountainous, with parts covered by thick forests making it easy for migrants to go undetected.

Most cases remain undetected to patients and their doctors alike.

Hepatitis E is a common disease worldwide, but it often remains undetected.