This was a British special forces operation by the 1st and 2nd Special Air Service to cross the Rhine river in advance of Field Marshal Sir Bernard Montgomery’s Allied 21st Army Group in 'Varsity' and 'Plunder' (25 March/3 May 1945).
After 'Overlord', the 1st and 2nd SAS were involved in a large number of operations in support of the Allied advance in France, most notably 'Bulbasket', 'Houndsworth' and 'Loyton'. After completing these operations both SAS regiments returned to the UK to regroup and refit after their manpower and matériel losses.
'Archway' was planned to support the landings of Major General Matthew B. Ridgway’s US XVIII Airborne Corps in the 'Varsity' airborne assault across the Rhine river. The SAS unit assembled for the undertaking was 'Frank' Force, so named after its leader, Lieutenant Colonel Brian Franks, commander of the 2nd SAS. This 'Frank' Force comprised two reinforced SAS squadrons (one each from the 1st and 2nd SAS Regiments), and numbered about 430 men mounted in 75 armed Jeeps, some of which were also equipped with 3-in (76-mm) mortars. The Jeeps were supported by a number of 15-cwt and 3-ton trucks.
The 1st SAS squadron was led by Major Poat and consisted of three troops, each consisting of three sections with three Jeeps. They had a 3-in (76-mm) mortar section at squadron headquarters, which also kept a reserve of 12 Jeeps. The 2nd SAS squadron under Major Power was similarly composed but had only two troops.
'Frank' Force’s first mission in support of the XVIII Airborne Corps took the form of short-range reconnaissance patrols ahead of three British formations (Major General E. L. Bols’s 6th Airborne Division, Major General G. P. B. Roberts’s 11th Armoured Division and Major General C. M. Barber’s 15th Division) on the eastern side of the Rhine in the area around Wesel. For this task the SAS detachment crossed the Rhine at Bislich in Buffalo amphibious tracked vehicles on 25 March.
'Frank' Force was then ordered to support Major General A. H. S. Adair’s Guards Armoured Division farther to the east in the area around the Dortmund-Ems Canal ahead of the advancing formations of Field Marshal Sir Bernard Montgomery’s Allied 21st Army Group. After this, 'Frank' Force operated until the end of the war with the 2/Welsh Guards, 8/King’s Royal Irish Hussars and the 15th/19th King’s Royal Hussars, which were the armoured reconnaissance regiments of the Guards, 7th and 11th Armoured Divisions. For this role the SAS had the advantage that its Jeeps were faster and lighter than the Cromwell tanks used by the armoured regiments.
The 1st SAS squadron working with the 11th Armoured Division was among the first British units to reach the Bergen-Belsen concentration camp, where the SAS troopers found between 50,000 and 60,000 inmates and then spent several days aiding the Field Security Police in hunting down war criminals and making several arrests.
Toward the end of April, 'Frank' Force was supplemented by the men and vehicles of the 'Keystone' party of the 2nd SAS under the command of Major Hibbert, and the combined SAS parties then fought several engagements against German army tank and infantry rearguards as well as units of the Waffen-SS, and reached Kiel on 3 May.