In this regard Viscount Cranborne acknowledged at the war's end that the Irish Government had '...been willing to accord us any facilities which would not be regarded as overtly prejudicing their attitude to neutrality', collaborating with the British war cabinet. (See below for complete text.) The pattern of co-operation between British and Irish agencies began upon the onset of war when de Valera permitted the use of specified Irish airspace mainly for patrolling coastal points. The use of the "Donegal Corridor", the narrow strip of Irish territory between County Fermanagh and the sea, was significant. By the autumn of 1941 use of the corridor was a daily routine. While de Valera rejected British appeals to use Irish ports and harbour facilities directly, de Valera was, according to M.E. Collins, 'more friendly than strict neutrality should have allowed.' The co-operation that emerged allowed for meetings to take place to consider events after German troops had overrun neutral Denmark, Norway, the Netherlands Luxembourg and Belgium. Three days after the fall of France, Irish and British defence officials met to discuss how British troops could, strictly at de Valera's invitation, occupy Ireland upon the event of a German landing there to expel foreign troops attempting to use her as a back door to later invade Britain (Plan "W"). The meetings continued, as Cranborne described, throughout the war, facilitating further dialogue.