States Visiting Forces At the invitation of the UK Government, the United States has had military forces (known as US Visiting Forces) permanently stationed in the UK since the Second World War. The 1951 NATO Status of Forces Agreement and the Visiting Forces Act 1952, along with other bilateral acts, establishes the legal status of the USVF in the UK. Several military sites within England are made available for the USVF's purposes. An RAF commander is present at the main USVF sites and is normally of the rank of Squadron Leader, whereas a US Colonel will normally command US personnel at each station. The role of the RAF commander is to liaise with the US base commander and act as head of establishment for Ministry of Defence employees. The use of UK bases for combat operations by the United States is a joint decision by both governments. The United States Air Force (USAF) 501st Combat Support Wing manages and supports operations at RAF Alconbury, RAF Croughton, RAF Fairford, RAF Menwith Hill, RAF Molesworth and RAF Welford, whereas RAF Lakenheath and RAF Mildenhall are managed by their respective host wings. MOD air weapons ranges Air weapons ranges (AWR) within the UK, previously operated by the RAF, are the responsibility of the Service Delivery (SD) part of the Defence Infrastructure Organisation (DIO). QinetiQ were awarded a three-year contract by the DIO in 2010 to manage the ranges but this role was taken over by Landmarc Support Services (part of Interserve) in 2014 as part of a contract covering the wider MOD Defence Training Estate. RAF stations and locations overseas Permanent Joint Operating Bases The UK operates Permanent Joint Operating Bases (PJOBs) in the four British Overseas Territories of Ascension Island; the Sovereign Base Areas of Akrotiri and Dhekelia in Cyprus; the Falkland Islands; and Gibraltar. The PJOBs contribute to the physical defence and maintenance of sovereignty of the British Overseas Territories and enable the UK to conduct expeditionary military operations. Although the Director of Overseas Bases, Strategic Command, controls and oversees the PJOBs. Semi-permanent operations The RAF have a semi-permanent presence at several overseas locations. Active military operations in the Middle East are supported by Expeditionary Air Wings which have been established at foreign airfields in the United Arab Emirates and Qatar. The RAF have a presence within Eastern European countries on a rotational basis as part of the NATO's Baltic Air