The July 1956 Suez Crisis brought US-UK relations to a low ebb, rendering the prospect of the use of US facilities in the near future remote. On 20 September 1956, the UK High Commissioner informed Menzies of the UK's intention to continue minor trials in March through October 1957, with another major test series in September and October. The main implication was that the range would be in use for most of the year. A minimum of 228 personnel would be required all year round, rising to 354 from March to July, and 400 from July to October. The codename Sapphire was initially allocated to the 1957 test series, but the RAF complained that that codename had already been allocated to the Armstrong Siddeley Sapphire aircraft engine. The name was briefly changed to Volcano until the Australians objected, and then to Antler.