About the event 

Operation Bletchley is a series of codebreaking challenges taking place 4 times a year for the Army Benevolent Fund. Complete all 4 in one year and be suitably rewarded! 

This spring, take on one of the UK's most innovative events as you tackle the fiendish codes, explore the great outdoors and learn more about our incredible heroes from the Second World War.

Challenge yourself and your family and friends to cover 100 miles* on foot in our Paris mission. Can you crack the code and deliver your message before it’s too late? 

*If 100 miles is too much/too little, you will also have the option to increase/decrease your mileage before the mission start date to suit your ability.

What do I do?

Sign up now and you will automatically create your own event page. This is so much more than just a place for your fundraising. You will use this page to track your walks, rack up your miles, mark off your cracked codes and earn fundraising milestone badges. 

You can link your page directly with Fitbit, Garmin or MapMyFitness to track your walks automatically or you can simply add your miles manually to your page. Instructions on how to do this can be found here. We recommend you do this at least 24 hours before the start of the event on 01 April. 

Use any device you like, the site is set up to work on your mobile, tablet or laptop, making it easy to keep track of your challenge wherever you are. Share this page with the whole world and watch the donations add up.

Cover your miles during April, and once you have cracked all the codes successfully and deciphered the final message you must deliver it by midnight on 30 April to receive your mission accomplished status and well deserved medal.

Crack all the codes successfully and deciphered the final message you must deliver it by midnight on 30 April to receive your mission accomplished status and well deserved medal. 


If you do not adjust your mileage and stick with the 100 mile challenge, you will receive your new code to crack after every 10 miles completed. These will be sent straight to your inbox. If you have increased or decreased your mileage, the codes will be delivered at every 10% interval of your total distance completed. 

You can choose to solve the codes right away, or save them up for the end. You'll need to solve the first 9 codes to solve the final code. 

Submitting your answers:

Submit the answer to each code in your event area on your fundraising page and find out instantly if you've solved each code correctly! To submit your answers simply follow these easy steps:

1.Log in to your page and go to 'Dashboard'

2.Click on 'Submit your answers'

3.Choose your level (Junior, Codebreaker or Cypher Expert)

4.Choose your code number

5. Enter your answer! You'll find out straight away if it is correct.


Your 100 miles can be completed anywhere in the world, whether is your local town, village or even if you live abroad. Whether you choose to increase or decrease your distance, you must finish before midnight on 30 April. You’ll have 10 codes to crack and once all the codes are successfully decrypted you must decipher the final message and deliver it. 

If you would like to adjust the distance to suit your ability, simply change this during registration or once registered, visit the 'My Fitness Activity' tab and you will be able to adjust it here (minimum of 20 miles applies - we can't be too kind to you Agents!).


This challenge is for everyone. Whether you are a beginner and want to get into walking or are a keen walker and want a bit of fun competition. You can do the challenge in your own time or race others to try and finish first with the added twist and codebreaking element.


The challenge runs from the 01 - 30 April. Feel free to keep tracking your steps until the very end. Your fundraising page will stay open until the end of May, but you must submit your final answer by midnight on 30 April to qualify for your medal.

Your official Operation Bletchley: Paris medal will be awarded if you receive 'Mission Accomplished' status by 30 April. You will need to break every code you receive and deliver the coded message on time.

In addition to your official Operation Bletchley medal there will also be a money can't buy fundraisers pin badge on offer. These will be awarded to anyone who raises £250 for the Army Benevolent Fund


We hope you will use your place in your Berlin mission to raise as much money as you can for the Army Benevolent Fund to support soldiers, veterans and their families. There are also plenty of rewards on offer!  The Army benevolent Fund is the official Charity of The British Army and will be there for soldiers, for life.

Have fun

Sign up and simply have fun testing yourself mentally and physically on your codebreaking challenge.