Editing Operation Bertram (section)

=== "Sunshields" for tanks ===

[[File:Wavell's idea for Sunshield tank camouflage.jpg|thumb|left|upright|Wavell's handwritten note and sketch proposing the Sunshield, 23 April 1941|alt=The original idea for the 'Sunshield', a handwritten note from General Wavell himself]]
[[File:WO201-2841 Middle East Command Camouflage Development and Training Centre, Helwan 'Sunshield'.jpg|thumb|'Sunshield' half open at the Camouflage Development and Training Centre, Helwan, 1941|alt=A tank with its 'Sunshield' camouflage half open in workshops near Cairo]]
[[File:IWM-E-18461-Crusader-camouflaged-19421026.jpg|thumb|A [[Crusader (tank)|Crusader]] tank in open desert, [[Mimicry|masquerading]] as a truck in its 'Sunshield']]

Real tanks were disguised as trucks, using light "Sunshield" canopies. They were made in two halves, which hinged on the sides of the tank. A half could be lifted by two men and fitted or removed in a few minutes.<ref name=Stroud80/> Different models of Sunshield existed to fit the various types of Allied tank which included [[Crusader (tank)|Crusaders]], [[Valentine (tank)|Valentines]], [[Grant (tank)|Grants]] and [[Sherman (tank)|Shermans]], mimicking different kinds of truck.<ref name=Lucas123/><ref name=Barkas202/><ref name=IWM/>{{sfn|The National Archives|2012}}

A total of 722 Sunshields were deployed in Bertram. According to Peter Forbes, "Sunshields were the most successful and the most exhilaratingly [[Mimicry|mimetic]] of the deceptions practised in the desert."<ref name=Forbes165>{{harvnb|Forbes|2009|pp=165–166}}</ref>

The idea for the Sunshield came from Commander-in-Chief Middle East, [[Archibald Wavell, 1st Earl Wavell|General Wavell]] himself. He sketched a tank mimicking a truck in a handwritten note:<ref name=Forbes165/>

{{quote|Is it a wild idea that a tank could be camouflaged to look like a lorry from air by light canvas Screen over top (sketch) It <s>might</s> would be useful during approach march etc. Please have it considered. 23/4 Wavell|Archibald Wavell<ref name=Forbes165/>}}

The note was passed to Barkas, in his words "not long after my arrival in Middle East... The whole idea was there. It was only a matter of design, development, and arrangements for manufacture."<ref name=Barkas202/> The first heavy wooden prototype was made in 1941 by Jasper Maskelyne, who gave it the name Sunshield.<ref name=Stroud80>{{harvnb|Stroud|2012|pp=80-81}}</ref> 12 men were needed to lift it, and it disintegrated on its first trial run on a Crusader tank. However, Barkas had enough confidence in the Sunshield to ask for a lighter version. The Mark 2 Sunshield was made of canvas stretched over a light steel tube frame. It was strong, light, and cheap to manufacture. And crucially, from as low as 500 feet, RAF pilots found that the Mark 2 convincingly resembled a truck.<ref name=Stroud80/>

The 722 Sunshields were carefully pre-positioned in the Martello tank-holding area near El Imayid railway station. Each was numbered. The crew of each tank was brought to Martello, told their number, shown where they would be parked and taught how to put up and take down the Sunshield, which they would have to do at night.<ref name=Barkas202>{{harvnb|Barkas|Barkas|1952|pp=202–203}}</ref>