Did Tunnock's exploding Tea Cakes deserve their Cold War V-bomber ban?

Three-quarters of a century ago, Tunnock's Tea Cakes were all the rage among airmen.

They would use the biscuit to stave off hunger while flying their nuclear bombers on long training sorties at the height of the Cold War.

However, one day, a snack-related incident led to catastrophe and the eventual demise of the Tea Cake.

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The story goes that following a Tea Cake explosion in a cockpit, they were added to the RAF's no-fly list and subsequently banned from flight.

But did they deserve this brutal classification? Was the cruel denial of Tunnock's Tea Cakes from pilots really justified? Do tea cakes really explode at altitude?

BFBS Forces News ventured to the RAF Centre of Aerospace Medicine to find out once and for all.

The experiment

The chocolate-covered biscuits with a marshmallow filling were lifted to 8,000ft, climbing at 4,000ft per minute, inside the altitude chamber – normally used in the training of new fast jet pilots. 

After that, the Tunnock's Tea Cakes were rapidly decompressed to 25,000ft in three seconds to see if they would blow up.

As air pressure in the chamber decreases, the air inside the item expands due to Boyle's Law until the object – in this case, a Tea Cake – breaks.

The tea cake incident

During the summer of 1965, a captain and student pilot forgot they had placed unwrapped tea cakes above their instrument panels.

When the captain pulled an emergency depressurising switch in a training mission, the iconic Scottish treat erupted.

Consequently, pieces of chocolate and marshmallow hit the canopy, flight controls and the men's uniforms.

But in the test, while the tea cakes did escape from their chocolate casing, they did not appear to explode and cause a risk to in-flight safety.

Furthermore, when the tea cakes were frozen before being placed in the chamber, their hardened shells were more resilient to cracking at altitude.

Pilots are also advised to keep the tea cakes in their foil wrapping until ready for consumption.