This has all been covered extensively in threads I and II.
To sum up:
- the situation of a lithium battery, if it was one, would have been located exactly where the flames can be seen in the airport video.
- the flames are being 'thrown' out as they would in a lithium-ion fire.
- the flames are crimson (metallic, and a lithium characteristic), orange and yellow, with white/grey smoke , also characteristic of lithium.
- diesel, plastics and tyre flames give off thick black smoke and only ignite at circa 500ºC.
- If the fire was due to vapour in the fuel tank (at the back of the vehicle) that would ignite as a fireball as at the tank.
- If as is claimed it was 'probably' an electrical fault, then if the power train was involved (say, from leaking diesel fuel or accelerants, such as antifreeze fluid or brake fluid the flames would most likely fan out from the centre of the car in a V-shape.
- The flames in the CCTV airport clip fan out from the left hand lower passenger seat side ONLY as of that stage.
- Arriving firemen decided it was too dangerous to remain in the building owing to noxious fumes - characteristic again of lithium battery fire. ( Five firefighters hospitalised and one airport staff.)
- A lithium-ion car battery does not need heat to catch fire. It can be a simple case of going over a speed bump and causing instability between a couple of cells within the battery to cause a self-oxygenating thermal runway.
- such a fire cannot just be put out by ordinary means as water could cause a hydrogen based explosion.
- Such a fire cannot be put out quickly it can burn for hours and even resume after a few days of appearing dormant.
If it was a 'diesel-fuelled only' vehicle it is quite a coincidence it matches a lithium-ion car fire exactly, even if it was an 'electrical fault' exacerbated perhaps by a leaking accelerant, as was the case at Newark Airport.
Other factors include the floors collapsing, which may or may not be to do with the incredibly high temperatures which would be reached in a lithium-ion car battery fire (2,000º) for the steel structure to give way (1,250ºC depending on type) and at least 600ºC is needed for the concrete to spall, much higher for it to melt completely away. It could be argued the combined temperature of several rows of parked cars, including EV-types would cause such a temperature. However, the construction company, Buckingham Group, were extremely experienced in large scale building works, including two premier league football stadia left unfinished, which indicates they would be well aware of public fire safety standards, especially after the Liverpool ECHO Fire 2018/19 and the ensuing recommendations in the Fire Report. Rows of parked cars would be a risk factor in the car park design and in choosing the strength of materials used in the infrastructure. The company did go into administration (or, rather a petition was applied for) five weeks before the fire. It seems water pipes had been installed but a sprinkler system never implemented, as was recommended from the Liverpool report. It is not mandatory to have one in a carpark. It could however point to Bucking Group skimping on material and labour due to its insolvent status and inability to pay suppliers and other creditors. So that could explain the various collapses. However, the car park was built within one year and post-Liverpool Fire recommendations, and bearing in mind Luton is a major international airport, with a nearby main motorway and main railway station (Luton is categorized as a 'London Airport', so you can imagine the sheer footfall and number of people on any given day, meaning safety would be of the highest paramount importance.
An ordinary diesel fire in a car wherein the driver was still present and able to call for help immediately should not have caused such devastation. Therefore, if it was NOT a lithium-ion fire of any sort, an explanation is required. And it had better be good.