Usually tougher than nazi bombs,anderson shelters, were named after home secretary John Anderson. He also served as MINISTER OF HOME SECURITy, A WARTIME DEPARTMENT, ATTACHED TO THE HOME OFFICE.

“While a properly installed Anderson shelter could withstand the effects of a hundred-pound bomb falling six feet away, Anderson shelters often leaked, were cold, dark and cramped and amplified the noise of falling bombs.”
http://www.iwm.org.uk/history/what-to-do-during-an-air-raid
While given free to people of limited means, others had to pay £7. Anderson shelters were useful only to the middle class because one had to have a garden (backyard in the US) as usually referred to in England. More than three million were eventually erected in gardens throughout those cities in England often bombed by the Nazis. (source: Warrior Race: A History of the British at War, by Lawrence James. 2003)

Unfortunately, the fourteen galvanized and corrugated steel plates which were bolted together to create the Anderson shelter weren’t waterproof. Unless one took extra measures, as many did, to make the shelter more comfortable, it wasn’t easy to get a restful night’s sleep. The shelters were often damp or even had standing water in them. They were cold. People waited until bombs got close to run to their Anderson shelters because they didn’t like being in one.

The reference to the landmine falling a few feet away is slightly inaccurate. What the Germans dropped were heavy sea mines which could break through heavy roofs, even ones made from cement, and the go off, creating a powerful explosion. Having learned this technique from the Germans, the Allies dropped sea mines on Nazi Germany.

Obviously, this was an upper working class family given how well the children are dressed and that they have a back garden which provided enough room to dug in the Anderson shelter. The box around the boy’s neck is his gas mask.

An Anderson shelter stands intact amongst a scene of debris in Norwich, c.1941
(photo courtesy Imperial War Museum)
“Anderson shelters – named after Sir John Anderson – consisted of two curved corrugated sheets of steel, bolted together at the top and sunk three feet into the ground, then covered with eighteen inches of earth. If constructed correctly, they could withstand the effects of a hundred-pound bomb falling six feet away. However, many Anderson shelters leaked, were cold, dark and cramped and amplified the noise of falling bombs.”
http://www.iwm.org.uk/history/what-to-do-during-an-air-raid