It has been claimed to be "one of the best pieces of footage of a big cat in the UK". This is my brief analysis of the big cat video UK.
First it has to said that this is simply not a big cat. If it is a wild cat it would be classed as one of the small wild cats (see Wild Cat Species). It is about 2 feet long (excluding the tail) and looks like it weighs about 20+ pounds. This is gauged by comparison with the tracks (apparently 4 feet 8.5 inches wide in Britain). This cat walks like a small cat or domestic cat meaning lightly and without that slightly arrogant and slower paced walk of the bigger cats. Its shape is neither cobby (stocky) nor slender. The smaller big cats like the puma and leopard are quite slender with long limbs. This cat cannot be either. It cannot be a lynx because there is no ruff.
This cat has been described as "fearsome" and a "panther" by the tabloid press. Well it is not fearsome it seems to me. And it is not a panther as this is a term to describe melanistic (black) leopards and pumas. The smallest leopard weighs about 20 kg (44 lbs pounds - small female Cap Province -- Wild Cats of the World) and are normally about 50 kg (110 lbs the size of female person). The puma is quite a large cat with some small cat characteristics and weights at the lower end about the same as a small women. Both are larger by a factor of about 4 or 5 than this cat.
Domestic cats can weigh on average about 8 lbs but some weigh over 20 lbs. The all domestic cat, the Maine Coon can and frequently does weigh over 20 lbs. But this cat is not a Maine Coon as the fur is short on this cat and the Maine Coon is longer bodied.
It is more likely to be a large (top end) domestic cat than a wildcat. And this cat is behaving like a domestic cat wandering down a railway line. This cat is not behaving secretively as a wild cat would. It is very hard indeed to see a Scottish wild cat. It takes a lot of tracking and patience.
One viewer of the video made the comment that it could be a domestic cat/Scottish wild cat hybrid (first generation). This could be the case. They are black apparently and although the Scottish wild cat is the approximate size of a domestic cat with hybrid vigor the offspring could be larger than the parents.
I think it is also worth mentioning that this cat is not very elusive, is it? It is calmly walking down a railway line in broad daylight when it could be hold up in a den and coming out at night as black panthers are meant to do. And why is this oh so fantastic video footage, some of the best ever pretty poor, frankly. Over all the tens of years we have been told about fearsome big cats in the UK the best evidence we have is this poor camera phone video of a 20 lb domestic cat!
Analysis of the Big Cat Video UK - conclusion: Can the papers please stop exaggerating as this is irresponsible and puts fear into some people who might react badly to the cat and try and kill it? Being at the very top end of the domestic cat range it is more likely to be a very large domestic cat or a Scottish wild cat first generation hybrid and it is certainly not a black panther.