With the news that Dippy the diplodocus is to be moved (next year) from his home in the main lobby of London's Natural History Museum, The Hub got to thinking about another plodding giant: the longer semi-trailer trial.

Launched back in what feels like prehistroic times (three years ago), it has evolved in order to survive and may yet find a place in the transport eco system, although not as the apex-predator it was originally conceived to be.

Much like a palaeontologist piecing together events from the fossil record - of DVSA allocation list as it's also known - it's been painstaking to construct an image of where exactly we now are with the trial.

You can read an in depth article on the trial's progress in the current Motor Transport (MT 26 January), but needless to say that despite all allocations having been finally made last autumn all of the trailers, three years on from the first launch of the trial, aren't yet running on UK roads.

Indeed, an FoI request from the start of December - in the absence of any detail from DfT - revealed that there were more than 400 longer semi-trailers 'missing'. A meteor strike is not thought to be to blame, this time, but rather the backlog of hard-pressed trailer manufacturers finding time and capacity to build the last few, given the improving economy has lead to full order books.

However, The Hub can confirm another reason for the discrepancy. Although the DfT set a tight six-week deadline for operators to take up and make use of the last few allocations last August, a spokeswoman for the department confirmed that in reality - and no doubt in a bid to finally get the allocations away - a generous grace period was applied in terms of operators sending through proof of order. This, much like a queue of triceratops at traffic lights, has caused things to back up.