 This was seen as excessive, and the Basel agreement in 1972 between the six existing EEC members and three about to join established a "snake in the tunnel" with bilateral margins between their currencies limited to 2.25%, implying a maximum change between any two currencies of 4.5%, and with all the currencies tending to move together against the dollar.This agreement also led to the formal end of the Sterling Area.The "tunnel" collapsed in 1973 when the US dollar floated freely.