• Families


IWM needs you, yes YOU, and your super-cunning spy skills for this mysterious Family Mission! Undercover agent and CBBC Presenter Ben Shires sets your top-secret mission from a hidden location…

Mission Briefing

Part of the Family Mission series created during the UK lockdown in Spring 2020. CBBC Presenter Ben Shires delivers your mission briefing.

[Agent Shires] Psst! Secret-agent Shires here: codename Speccy Squirrel and I urgently need your help with this week's IWM Family Mission! Everything that you need to know is written on this piece of paper. What do you mean there's nothing on it? Of course, there is! All you need to do is- what's that? Someone's coming!  

[Ben Shires] That's so weird I could've sworn I just saw someone in my back garden... Anyway, enough of that. I'm Ben shires and I'm here to tell you all about this week's IWM Family Mission. Apparently, it's written on this piece of paper, but it looks blank to me. What's going on? It- hang on that sounded like a knock at the door. I'm just going to get that. 

[Agent Shires] Thank goodness he's gone! Now for this week's mission. Spies like myself have to think on our feet when it comes to inventive methods of deception. From silk maps to inflatable tanks and even fake feet to hide our footprints. I've written your instructions for this week's mission in invisible ink. It's a highly complex solution – a mysterious liquid that disappears when it hits the page and only reappears again under lamplight. It's an incredible liquid I like to call lemon juice. Oh, it's bitter!  

Your mission this week is to create your very own top-secret spy identity card featuring your codename and of course your special skill. All you need is some lemon juice, some plain white paper and something to write with like a paintbrush or a cotton bud. That way your secret identity will remain secret and only you and fellow spies will know to hold it under lamplight, exposing it to heat and revealing all. And yes, before you ask, we spies really do use invisible ink!  

Remember the special agents at IWM have relied all the information for this week's mission over on the website. Well, that's it. Off you go! Good luck and remember: shhh!  

Now that Agent Shires has relayed your Family Mission brief, you’ll find everything you need below, including your instructions to create your top-secret IWM identity card including your very own top-secret agent code name.

Top-secret IWM identity card

What you’ll need:

  • White paper
  • Paintbrush
  • Bowl
  • Water
  • Lemon Juice
  • Desk Lamp

Top-Secret Tip! Agents can also use a toothpick or cotton swab to write with and if you don’t have any lemons to hand you can use milk, orange juice or vinegar!

What to do:

  1. Squeeze some lemon juice into the bowl and add a few drops of water.
  2. Mix the water and lemon juice with a spoon.
  3. Dip the paintbrush into the mixture and write your top-secret identity card onto the white paper.
  4. Wait for the juice to dry so it becomes completely invisible.
  5. When you are ready to read your secret message or show it to a fellow secret agent, heat the paper by holding it underneath the light bulb in your desk lamp.

Top-Secret Tip! Agents must have an older agent to help them with this mission. Fieldwork can be risky so please take care.

Top-secret agent code name

Follow our fool-proof formula:

  1. Your favourite colour.
  2. Followed by the last thing you ate.

Example agent names at IWM include Red Apple and Purple Porridge!

Agent Shires' Secret ID Card

  • A piece of paper with an invisible message not yet visible.


    No secret message to see here!

  •  A piece of paper featuring a secret message that has been revealed.


    Agent Shires' secret identity is revealed!

Did spies really use invisible ink?

Josephine Baker rehearses a new song with Vincent Scotto in liberated Paris.
Josephine Baker rehearses a new song with Vincent Scotto in liberated Paris. © IWM FRA 100467


Josephine Baker was a hugely popular entertainer who became famous in Paris in the 1920s. She used her fame as a cover to spy for the French Resistance during the Second World War. No one suspected that her sheet music was covered in invisible ink and her stardom enabled her to attend parties with high-ranking officials and report important information.

Lemon Juice

Invisible inks hidden in a bottle, with wooden casing.
Invisible inks hidden in a bottle, with wooden casing. © IWM EPH 10053

Lemon juice is an organic substance that oxidizes and turns brown when heated. Diluting the lemon juice in water makes it very hard to notice when you apply it to the paper, no one will be aware of it’s presence until it is heated and the secret message is revealed.

Need some inspiration? Take a look at some fellow agents from the Special Operations Executive (SOE) in the Second World War below.

Don’t forget to tell us how you get on or even better show us your IWM identity card on IWM’s Facebook and Twitter (we promise we won’t reveal your top-secret identity to anyone!)

Good luck agents!


Noor Inayat Khan

Code Name: Madeleine

Noor Inayat Khan was a fluent French speaker and served as a wireless operator with F Section, Special Operations Executive. After joining the SOE and signing the Official Secrets Act, Noor began agent training including physical training learning how to defend herself without weapons, map reading and specialist signals training so she could encode and decode secret messages.


Yvonne Cormeau

Code Name: Annette

Fluent French speaker Yvonne Cormeau was a wireless operator parachuted into France in August 1943. She sent a record number of 400 transmissions in 13 months – the highest of any SOE wireless operator. Yvonne transmitted from a remote village with no running water for six months. Even when the Germans became aware a female wireless operator was transmitting in their area she managed to evade capture – they were convinced no Englishwoman would stay in such a place!


F. F. E. Yeo-Thomas “Tommy”

Code Name: The White Rabbit

F. F. E. Yeo-Thomas or “Tommy” as he was known added two years to his age in order to join the Army in the First World War and later joined the R.A.F when the Second World War began in 1939. A fluent French speaker, Tommy joined the SOE in 1942 and undertook three missions into occupied France, once managing a safe return to SOE headquarters in London by hiding himself in a hearse!

Explore Further

Adventures in History: Spies in Disguise graphic
Home Learning

Spies in Disguise

Head and shoulders portrait of Mrs Yvonne Cormeau who served as as SOE Wireless Operator in France.
© IWM (HU 47367)
Second World War

Seven Stories from Special Operations Executive

Special Operations Executive (SOE) was created during the Second World War with the instruction to ‘set Europe ablaze’ - discover the stories of some of the men and women who served.

A member of the French Forces of the Interior (FFI) uses a truck for cover during gun battles with German snipers in Dreux, August 1944. During this period several French towns were liberated by the FFI in advance of Allied forces.
© IWM EA 33757
Second World War

Spies, Saboteurs And D-Day

Resistance groups were active throughout German-occupied France and made important contributions to the Allied invasion of Normandy in June 1944. Special Operations Executive (SOE) had been set up in 1940 to coordinate and carry out subversive action against German forces in occupied countries, including France.


Family Mission has been created with the generous support of Old Possum's Practical Trust