Historical Note 

Last week Time Warner vice  chairman apologized for joking that Polish  soldieres clear mines with their feet. In fact, a Polish officer invented the first practical electronic mine detector during World War II.  In the winter of 1941-42, the British War Office invited designs for a  robust and reliable mine detector.  The one they adopted was submitted  anonymously by Lieut. Jozef Stanislaw Kozacki, a signals officer with the  1st Polish Army Corps stationed in Scotland following the German defeat of  Poland in 1939. His invention was tested and developed and 500 Mine  Detectors No. 2 (Polish) were rushed to the Western Desert in time for the  advance on El Alamein. Their effect was to double the speed of British troops through the heavily mined sands from 100 to 200 meters an hour.  
The same basic design continued in use for 50 years and last saw the action with  British forces during the 1991 Gulf  War. 

From: "The History of Landmines" by Mike Croll (MRC329@aol.com), first  published in Great Britain in 1998 by Leo Cooper, an imprint of Pen &  Sword Books Ltd., 47 Church Street, Barnsley S270 2AS,  ISBN 0 85052 268 0: 
Page 54:  (discussing the 350,000 mines laid on the English beaches to deter an invasion)  
 
"The mining of the beaches had several unexpected consequences. As the  defence of Britain became more organized it became necessary to move or to re-lay minefields. The laying of the original fields was so poor that entirely new methods of clearance, laying and accurate recording had to be devised. The difficulties of locating buried mines in the shifting sands of the beach 
prompted the War Office to issue specifications for a mine detector during the winter of 1941/42. The design accepted was submitted by Lieutenant Jozef Stanislaw Kozacki, a Polish signals officer who had escaped to France and then to Britain in 1940. 

The Polish detector had two coils, one of which was connected to an 
oscillator which generated an oscillating current of an acoustic frequency. The other coil was connected to an amplifier and a telephone. When the coils came into proximity to a metallic object the balance between the coils was upset and the telephone reported a signal. The equipment weighed just under 30 pounds and could be operated by one man. The Polish detector saw service throughout the war and the Mark 4c version was still used by the British Army until 1995. The experience of mine warfare gained on the Home Front was to prove useful throughout the war. While the Germans dominated mine design and mine laying, the British were the great innovators in clearance techniques, initially as a result of their own shortsightedness." 

The below text is from the book "THE POLISH CONTRIBUTION 
TO THE ULTIMATE ALLIED VICTORY IN THE SECOND WORLD 
WAR" by Tadeusz Modelski: 

Page 221: 
"The thirteenth Polish invention: at the end of 1941, the technical 
unit of the Polish General Staff in London introduced the British 
Ministry of War production to a new improved model (the old 
model was invented in Poland in 1937) of the mine detector 
constructed in Scotland in 1941 by the Polish engineer, J. Kosacki. 
The British authorities accepted it as the best one of its time, 
praising the Poles, and ordered mass production, under the name 
of "Mine Detector Polish Mark I". All of the British Army was 
issued with the detector; 500 mine detectors were used by General 
B. Montgomery's Eight Army, to clear the terrain before the El 
Alamein attack." 

Polish Mine Detector 

This name was given during World War II by the allied forces to a 
contraption invented by a recently deceased polish engineer Jozef Kosacki. 
His friend Jan Zakrzewski, who was an officer in the Polish Communication  Training  Center in St. Andrews in Scotland  told this story to the press.  He said: „Kosacki, while still in Poland, was researching radio waves, he  came up with the idea of a machine which would find hidden in the ground  metal items. In St. Andrews he was given a laboratory and a sergeant as an aide. He showed me what he constructed. It looked like a small box with an antenna. His research became an interest of the commanding officers of the British Army. All those, who knew, what he has been working on, were obliged to sign a secrecy agreement. One day, Kosacki was called to London. Experts agreed that production must be started immediately. Kosacki's mine detectors were already used in the North African campaign. His discovery was not patented; he gave it as a gift to the British Army. He was given a thank you letter from the king for this. The English were very happy that they could bring something to the cooperation table with the Americans that they did not have."