I have discussed this topic for 20 years or more with others and find the similarities with the posts above to be interesting. I believe the best (and probably only) time for Great Britain to acquire the Suez is at the Treaty of Sevres signed on 10 August 1920.
Some legal background is important to understand. The British occupation of Egypt in 1882 was never formalized, and the Pasha of Egypt remained legally a subject of the Sultan. The British declaration of war on the Ottoman Empire on 2 November 1914 forced a change in the status of the Pasha (and therefore the province of Egypt.) Egypt was declared a British Protectorate, and King George V replaced Sultan Mehmed V as the Pasha’s sovereign. Egypt is not an independent country and her boundaries are therefore not internationally recognized.
The Treaty of Sevres gives an opportunity for Britain to permanently secure her military and commercial interests in the Suez. The entire Sinai Peninsula and a zone 20 miles west of the Suez Canal is severed to form a new Suez Protectorate. Approximately one-quarter of the 20 mile zone is under the waters of the Nile Delta, and the remainder is open desert with few inhabitants. 20 miles is sufficient from the standards of 1920 to protect the Canal from attack.
The severance of the Suez Protectorate would be highly unpopular in Egypt, but the timing of August 1920 is excellent from the British point of view. The Wafd Independence Movement launched an open rebellion in March-April 1919 which was crushed by the some 400,000 British Commonwealth troops awaiting demobilization and transport home. Virtually all Egyptian nationalists were in British jails or exile. The remaining Egyptian leadership was polarized and ineffective. The British, especially Field Marshal Edmund Allenby who was serving as High Commissioner in Egypt were aware the 400,000 troops had now gone home, and any future revolt would strain resources. Thus preparations for unilateral grant of Egyptian independence on 28 February 1922 were well underway. One major influence on FM Allenby’s actions was his belief that with modern communications, Cairo had lost much of its importance to Great Britain.
It was quite possible to tie Egyptian independence and the Suez Protectorate into the final draft of the Treaty of Sevres. The Egyptians have a choice between rejecting both, or accepting an independence that is unexpected. In the power vacuum existing in Egypt in the summer of 1920, I believe Pasha Fuad would accept independence and elevation to the status of king. Acceptance via the Treaty of Sevres also gives the Egyptians the legal right to force the withdrawal of British forces from Egypt. This is quite acceptable, the British garrison of three brigades – Cairo Cavalry, Cairo Infantry and Canal infantry is just adequate to protect the Suez. The floating drydocks and stores at Alexandria can be moved to Port Said or Haifa.
The Suez Canal Concession will be terminated, although the revenues due to the Pasha from the Suez Canal Company will continue. Eventually, King Fuad can legally force a dissolution of the Anglo-Egyptian Condominium in the Sudan, acquiring the Arab West and North and leaving the British with the Black African East and South.
Is the Suez Protectorate viable? The 1927 Encyclopedia Britannica set that got my father through college seems to indicate the answer is yes. The population of the Suez Protectorate area excluding nomadic Bedouins is estimated at about 88,000 in 1920. About 15% is European with the nationalities represented in ranking as Greek, Cypriot, French, British, Maltese and Italian. The largest employers of Europeans are the Suez Canal Company and the Egyptian Protectorate. It appears that British military personnel were not included, but after the withdrawal from Egypt would number about 9,000 Army, 800 RN and 500 RAF personnel, with few dependents outside of officers, senior NCOs and senior Other Ranks/Ratings. This is my estimate only.
The population is distributed as follows: Port Said – 52,600, the main commercial hub and center of the Suez Canal Company. Considerable light industry geared to support of canal shipping. A ferry serves rail connections on both sides of the canal.
Ismailia – 15,918, terminus of the Nile Canal providing fresh water to the entire protectorate and irrigation to the largest agricultural zone. (Kind of an exact count for an estimate.)
Suez (including Port Tewfik and Port Ibrahim) – 9,091, southern terminus of the Canal with a small drydock at Port Tewfik. Port Said on a much smaller scale.
El Arish – 4,632, commercial center with a seasonal agricultural output; site of a major rail repair center built by the British Army in 1917, and a major RAF station since 1916.
Kantara – 1,562, major base for the Canal Infantry Bde.
Abu Suweir – 1,530, site of the largest RAF base in the Protectorate, built in 1917.
El Kubri – 725; Taba – 450; El Rumania – 385; El Tor – 210 (site of a quarantine station); Sharm-el-Sheik – 182, site of a RN Observation post; Nuweiba – 170; El Kuntilla – 150 (border post); El Quseima – 150 (border post and abandoned rail terminus); Nabq – 150 fishing port; El Thamad – 120.
One additional site, Nakhl is occasionally inhabited for mining iron, copper and zinc when market shortages make it profitable.
Other places of note: Fayid is established as an RAF base in April 1921 and by 1930 had a population of 980. Oil was discovered in 1922 near Abu Durba which had an estimated population of 750 in 1930. Port Fuad opposite Port Said was established in December 1928 and in 1930 had an estimated population of 1500.
Manganese and iron mining began in scale at Abu Zenima in 1932.
What does the future of the Suez Protectorate hold? I doubt the Arab population would increase much, and may well decline. Those employed by the Pasha would be replaced by British Commonwealth nationals. Others may find attractive opportunities in an independent Egypt, and manual laborers would be sought from the British Commonwealth. Most mechanics and technicians for the expanding automobile and aviation fields will also come from Great Britain. As with South Africa, Kenya and Uganda, small business and craftsmen from India will arrive and likely displace some Egyptians. A public school system will be established, bringing their staff primarily from the Caucasian Commonwealth. Graduates will assimilate into British identity as opposed to their Greek, Cypriot, French or Maltese parents. British expatriates will filter in, former military, due to low cost of living, etc.
For the first 15 years the Suez Protectorate is probably fairly stagnant, as is most of the Empire. This is one of the few parts of the world not affected by the Great Depression. The Italian invasion of Ethiopia will bring considerable modernization and expansion of the Army and RAF garrisons. The naval facilities will also be expanded and improved. Local industry will also expand, both to support the garrison but also in commercial sectors.
The Second World War is an open question. If Mussolini did invade Egypt, then she is forced into the war as an active ally, and not as an occupied neutral. If he does not, then British, Australian New Zealand and Indian troops will focus on an early conquest of Italian East Africa. This may force Mussolini’s hand. An invasion of Egypt is his only chance of rescuing his isolated colonies on the Red Sea. If Italy respects Egyptian neutrality then the British will have a tough time going on the offensive in the Eastern Mediterranean.
By the 1950s, the Suez Protectorate will be solidly British in popular sentiment and see little value in independence. In effect it has become a larger Gibraltar. The buffer zone of the Suez Protectorate can only be considered an advantage for the Israelis in 1947-49.