This question was asked here recently:
And it has produced some very solid analysis and fascinating statistics.
But the USA had a very different experience of war to the UK. The UK fought for longer and more intensely (the Germans could bomb UK factories and much of the UK supplies had to be shipped in in convoys suffering frequent U-boat attack).
So the need to exploit every scrap of metal like iron and aluminium was far greater. So the UK ran similar "recycling" efforts to the USA but possibly on a more extreme scale. For example, virtually every cast-iron fence on both private and public buildings were removed (the effects are still visible in the majority of pre-war buildings). See this BBC description of the situation:
As an island nation, when war broke out in 1939, Great Britain was dependent for so many of its supplies on imports by sea. The days of significant air cargo traffic had yet to arrive but would have been equally vulnerable to enemy attack. Although the term was not used in those days, there was an immediate recourse to recycling to conserve scarce resources. Garden railings were removed for their scrap metal and aluminium kitchen saucepans were collected for their potential in the aircraft industry.
Some people doubt that the metal collected was used in the war effort:
...One way used was to requisition the 19th century iron railings and gates surrounding many of the cemeteries, parks and squares in Britain's towns and cities. This was done in 1940 when many hundreds of tons of iron were removed by the authorities. The public were also asked to donate aluminium kitchen utensils - although in practice these were only owned by the better off. Beaverbrook himself issued a press appeal: "We will turn your pots and pans into Spitfires and Hurricanes, Blenheims and Wellingtons".
Since then the rumour has persisted that the iron collected was unsuitable for making planes and instead buried in quarries or dumped at sea, and that it was basically just a propaganda effort. The Public Records Office does not have any records of what happened to the iron collected, it seems the records disappeared or were shredded after the war. In 1978 a journalist claimed the London iron was loaded onto barges and dumped at sea in the Thames estuary.
The issue of whether the iron collected was useful for the war effort was even raised during the war as Hansard shows (worth reading also because the volume of collected scrap is mentioned):
When it is realized that the basis of all our armaments is iron and steel and that in order to make iron and steel you must have scrap, it will be agreed that what was done was necessary for the prosecution of the war.
Were the recycling efforts in the UK far more significant for the war effort than the related efforts in the USA? Or was it just for propaganda purposes?