The Scottish government guarantees that cancer patients will be treated within 31 days of diagnosis, but this guarantee only covers the period until a patient has had surgery.

BBC: Months-long wait for radiotherapy at Inverness hospital

"There is no way in this modern world that you can guarantee a job for any period of time in any part of the world, " he told me.

CNN: 'THE PEOPLE'S ASPIRATION'

Russian engineers will certify, or "guarantee", the performance of the return capsules for a fixed period.

BBC: November deadline for ISS crews

Out of 58, 070 patients, seven missed the 12-week guarantee, but they were treated within a few days of that period ending.

BBC: A&E department

Seven letter bombs were sent over a period of three weeks and the police have warned that they cannot guarantee that there will not be another one.

BBC: NEWS | UK | Letter bomb suspect is arrested

Unfortunately, development of the new jammer coincides with a period when Pentagon investment in new technology is expected to decline markedly, so there is no guarantee the Next Generation Jammer will stay on track.

FORBES: In Digital Age, U.S. Military Still Stuck With Vietnam-Era Jammers