The air force takes the load

As we said, Air Vice-Marshal Conyngham had a chain of landing zones prepared going deep into Egypt, so he was prepared for any rapid withdrawals. A great effort was made to increase the size of the Desert Air Force that would help slow the Axis advance. So much fighter strength was shifted to the desert that the defence of the Nile Delta was left to some Beaufighter night fighters and a few Spitfires. One bright spot was that there was finally a full squadron of Martin Baltimore day bombers. They were supplemented at night by a Blenheim squadron (no longer fit for day bombing). The size of the threat to the Middle East was finally realized and aircraft destined for India and the Far East were diverted to the Middle East. This is based on the account in Vol.III of the Official History.