I took some advice on this matter in 2003 - it is correct to say that Jeremy did say that the line went dead, and that there was no engaged tone...
However, I was reliably informed that this type of phone (round finger dial model) was prone to faults where the plungers often got stuck in the down position, which effectively cut off any line of communication, without leaving so much as a dialing tone...
This type of fault could be brought about if the phone received a hard knock - resulting in the plunger becoming stuck in the down position. What is not clear, is if the plunger which was stuck in the down position could be freed by giving the phones cradle another hard knock or bang, and what the status would be to enable the operator to open up the line so that police at the incident room could eavesdrop?
What does become clear, however...
Is that Jeremy states that when he tried to call whf back, he got the engaged tone, a fact which was confirmed when the police also tried to establish contact with the farmhouse, and so one is left with the impression that somebody at whf could have simply depressed the cradle and held it down for several seconds without allowing it to spring back up into the open position...
This could have been done for a few seconds and then the hand that was holding the cradle down could have let go, and left the handset off its cradle. What is clear by studying all the facts relating to this matter, is that when the operator checked the line, she confirmed that the handset had simply been left off the hook - so that if anyone tried to make contact with the farmhouse, they would be met with the engaged tone...
The phone at whf was never an open line to another outside number...