Can’t help with any Martinet serial though (if, of course, that is what it is). Sure it’s not a Firefly FR.1 (examples of which were definitely dumped there too)?

Surprising how similar the two tail profiles are, what errs it on the side for Martinet for me is the tail plane positioning seems to far aft for the Firefly, (Martinet elevators come aft of the rudder hinge line) but maybe that is a trick of the angle it was taken at?

All: If you havn’t done so already, read a copy of ‘Empire Of The Clouds’ before you see the Sea Vixen this season. After you’ve read this brilliant book, the display will have a time-travel element to it.

Far, far better is the John Derry biography by Brian Rivas.
I really do urge people to seek out this thoroughly researched (both family and aircraft wise), and personal story of an outstanding test-pilot and the DH.110 (Sea Vixen predecessor) test and display programme up to the terrible accident at Farnborough – 60 yeras ago this coming September.
This book was a huge influence on my aviation interest when I first read it in the ’80s, I even managed to get my missus to read it recently and she was sobbing at the end of it!
The book has recently been re-released and can be found at good prices on Ebay & Amazon.

Simon Hargreaves is the most recent display pilot of XP924.

Could that be your Master/Martinet back end behind this Firefly?

I would say yes, isn’t that the Attacker back end, prominant in your earlier shot, just behind it? You can just make out the tailplane up at an angle (immediate right of the skinless Martinet ? rudder) with the elevator horn balance sticking up.

Interesting set of pictures as you can just about work out the relative positions of the aircraft.

Firefly to the left.
It does look nearer to Martinet fin/rudder than a Firefly, especially the rudder line and the relative position of the tailplane.

I’ve seen one bolted to an aircraft!
I realise thay are tall, compared to say a Hunter, but surely no bigger than a Lightning?
I can see why a half (or is it a quarter?) cockpit is handier, just seems a shame to loose the rest of it, especialy as the type has a fairly distinctive front end.

It might do, it’s been halved in height and length!
Shame as a full F-84 cockpit would be far more attractive, unless this is based on a sim/procedures trainer?

This is my take on it (and to be read with my previous posts),

At the MoD Procurement level the aircraft would have had to have fitted the standard British name and role designation, Phantom F.3 being it.
There are many examples of APs not following the exact official titling (this came up in another thread recently), and so it doesn’t surprise me at all that the RAF litrature shown so far does not show ‘Phantom F.3’, but rather ‘F-4J (UK)’.

I’m trying to emphasise the difference between Mod PE and the RAF, I don’t doubt for a minute that most people involved with it referred to it as the F-4J (UK), there must have been much kudos in keeping an American designation, particularly on such a well known and ‘cool’ type.
However I struggle to believe that this would have been a unique example of an aircraft brought by the MoD and not to receive a proper designation.

In Vic Flitham’s book ‘Aircraft In British Military Service’ the type is referred to as Phantom F.3, he also mentions that the title was short lived and F-4J gained favour.

There are just too many sources for F.3 to be an entirely made up designation, various quality publications, Fujimi, Hasegawa, etc.

I think Maple may have hit the nail on the head that the dropping of Phantom F.3 seems coincidental to the service entry of the Tornado F.3, but I still stick to my points in post #189, there are just too many types with the same designations for that to have been an official concern.
F-4MPhixers post mentions that the aircraft were released by McDD/NASNI, as F-4J (UK)s, I wonder if that is another reason why that name stuck and became popular?

In short I believe it was known as F.3, all be it briefly and within the MoD, while F-4J(UK) is what most other people called it.:)

I’m happy that Topspeeds’ post remains, I must really get some images together.