I'm not going mad - I remember this vividly. Back in the seventies BBC2 would have a ten minute time slot (I think between 8:50 and 9pm) which they filled with varying 'themed' programmes each night. They ran a paranormal series in that slot for a few weeks - reports from ordinary men and women relating what they had seen or experienced which could be construed as paranormal.
A husband and wife were sitting telling their story of how they came out of a pub drunk, and cut through Hyde Park to get home...the husband embarressedly confessed that he was so scared at what they saw that he deserted his wife and ran away. They both said they were confronted by a taller than man 'beast' covered in fur (almost a cross between a bear and a 'werewolf') which roared at them. It looked as though it was about to attack them which is why the husband ran away. Of course I was laughing at this point and thinking 'Yeah, yeah I'm sure you saw a beast just like that' - when the woman described how it attacked her and clawed at her as well as biting her. I was still thinking 'Yeah, yeah' - when she suddenly opened her blouse to show the most horrific scarring and a missing breast. It seems she spent months in intensive care and a large scale Police hunt was made for whatever did it to her - but nothing was ever found.
You can read more on the beast of Hyde Park here.