Modern immigration border controls originated in 1905, although some means of controlling foreign visitors to the United Kingdom existed before then. Although the Aliens Act 1793 was passed and remained in force to some extent until 1836, there were no controls between then and 1905 barring a very loosely policed system of registration on entry.

History

Aliens Act 1905 and the Immigration Boards The beginnings of the modern-day UK immigration control can be traced from the final decade of the 19th century and the political debate that grew surrounding the perceived growth in the numbers of Eastern European Jews coming to the UK. Political alarm was also expressed regarding the rising numbers of foreign national criminals in UK prisons, the growing demands on poor relief within local parishes and fears of degenerating health and housing conditions.

There was particular focus on the large numbers of Russian and Polish Jews who had arrived in the East End of London after fleeing persecution in the Russian Empire. In 1898 the Secretary of the Board of Trade reported a "…stream of Russian and Polish immigration—in other words, the immigration of the most destitute type...increasing in volume year by year". The numbers of arrivals were highly debatable owing to the deficiencies in available statistics. Concerns focussed on perceived overcrowding in the East End of London.

The legislation that finally emerged was the Aliens Act 1905. It was easily evaded, and did not even require Immigration Officers to give written permission to land or stamp a passport – permission to land was given verbally.

It was, however, the first legislation to define some groups of migrants as 'undesirable', thereby making entry to the United Kingdom discretionary, rather than automatic. The Act ensured that leave to land could be withheld if the immigrant was judged to fall into one of four categories: a) if he cannot show that he has in his possession ... the means of decently supporting himself and his dependents; b) if he is a lunatic or an idiot or owing to any disease of infirmity liable to become a charge upon the public rates; c) if he has been sentenced in a foreign country for a crime, not being an offence of a political character; or d) if an expulsion order under this act has [already] been made.

People refused entry under the act were given a right of appeal to the Immigration Board in charge of control of one of the designated ports listed by statute and the practical application of the control was conducted by the new Aliens Inspectorate and its officers, the first Immigration Officers, who were hurriedly recruited from within the existing ranks of HM Customs and the Board of Trade. Their basic task was to test whether the traveler had means of support which might be proven by either presentation of cash or evidence of a firm offer of employment. The inspection generally took place aboard ships or in “receiving houses” on shore. The anomalies within the regulations meant that it was common for passengers to evade the control by the simple means of posing as 2nd or 3rd class passengers or sharing the evidence of funds between them. The head of the new organization was titled HM Inspector and its first incumbent was Mr. William Haldane Porter.

1914–1918: Immigration control during the First World War 1914 marked a landmark in UK immigration control in that it was only from this point that every person entering the country had to produce evidence of identity. The Aliens Registration Act 1914 was rushed through Parliament in a single day on the eve of the First World War and allowed stricter controls than before including the power to make aliens aged over 16 register with the police. The power still remains in use. Although the Aliens Act 1905 technically survived until its repeal in 1919, it was, in practice, submerged by the far more stringent powers of the Aliens Restriction Act 1914. The 1914 act contained a clause which gave the Home Secretary power to prevent the entry and order the deportation of aliens if it was deemed 'conducive to the public good'. For the purposes of the 1914 legislation immigration officers were re-titled Aliens Officers and the service was a compound of Home Office staff and Customs staff.

In order to mark someone's arrival and departure the new Aliens Officers endorsed the passports of passengers with red stamps on arrival and with black stamps to cancel the endorsement on the persons departure. In April 1915 an Order in Council was made that no alien passenger was to be allowed to land unless he held either a passport with a photograph attached issued within the two preceding years, or some other document establishing his national status and identity. Prior to this passports had not contained photographs and had not been stamped in any way.The Key in the Lock - TWE Roche, 1st ed p. 83–84

From April 1915 only passengers with exit permits were allowed to leave the UK, and then only from certain ports. In an extension to their duties that would be repeated during the Second World War, officers were tasked with retrieving ration documents from departing passengers. In 1916 a “Traffic Index” was created from the landing and embarkation cards collected at ports and matched together at the Home Office's Aliens Branch HQ to show whether the person had complied with their conditions of entry. This simple process was the only mechanism for measuring the effectiveness of the control and continued until 1998 when embarkation controls were abolished. By 1920, the number of Aliens' Officers had reached 160.

Immigration controls in the 1920s and 1930s

The Aliens Order 1920 was a statutory instrument made under the 1Aliens Restriction Act 1919. Brought out in the context of widespread unemployment after the First World War, it required all aliens seeking employment or residence to register with the police. The order drew its powers from the 1919 act and granted a wide-ranging discretion to the Home Secretary. It stipulated that no alien might land without the permission of an immigration officer, by way of a passport stamp, and granted powers to attach conditions to the grant of leave, to refuse those who could not support themselves, and their dependants, those medically unfit and those convicted of crimes abroad. It gave the power to demand documents satisfactorily establishing identity and nationality. It restricted the employment rights of aliens resident in Britain, barring them from certain jobs (in the civil service, for example), and had a particular impact on foreign seamen working on British ships. It required people seeking employment in the UK to obtain permission from the Ministry of Labour, which was of huge significance in establishing a link, for the first time, between immigration control and the employment market. It also targeted criminals, paupers and ‘undesirables’, and made it illegal for aliens to promote industrial action – a response to fears of imported revolutionaries following the still recent Russian Revolution. Further motivation to extend restrictions on foreigners was driven by post-war unemployment and the consequent desire to safeguard jobs for indigenous Britons. The 1919 act was renewed annually until 1971 until it was replaced by the Immigration Act 1971.

A new dimension to the work arrived in the 1920s where the influx of visitors to the Wembley Exhibition meant that the traffic generated by air travel could no longer be ignored. It was decided to appoint one immigration officer to deal with incoming passengers at the main London airport in Croydon. By 1925 the Immigration Officer at Croydon Airport was dealing with 15 aircraft movements per day. By 1937 the total numbers of people arriving by air reached 37,348, still a paltry number when compared to the numbers arriving by sea, 498,326.Home Office Statistics of Foreigners Arriving in the United Kingdom, 1959, HMSO, Cmnd 994 The numbers arriving at seaports would continue to rise, but would be outstripped by the late 1950s by the rise of air travel.

The 1930s were marked by the ever-increasing numbers of refugees arriving from Europe fleeing from Nazi Germany. Refugee arrivals rose from close to zero in 1930 to 3109 in 1933. By 1938 the annual figure was 11,000. After 1936 the figures were augmented by the numbers fleeing from war-torn Spain. Although there was no publicly stated policy for the admission of political refugees before 1971, a settled but implicit approach had emerged during the 1930s. The handling of refugees was largely dependent on their being able to show that they could maintain themselves or be maintained. The Immigration Service cooperated with the Jewish support organizations who worked to provide support or provide sponsors but there was no agreed international approach to the handling of refugees. A Home Secretary memo to the Cabinet in 1933 shows that efforts were made to take a flexible approach but admitted that some refugees, ("a few") had been refused and returned to France where they awaited a relaxation of the rules. Restrictions placed on Jewish refugees were based mainly on economic fears for the employment market.National Archive - memo to Cabinet 1933 - Jewish refugees

Statistics for 1938 and 1939 show Germans as being the top nationality refused entry for both yearsForeign Nationals Entering and Leaving the UK 1938-1951, HMSO - Germans refused in 1938, 274; 1939, 481 and it is likely that a large proportion of these were potential refugees being returned to an uncertain fate. That said, the UK admitted more Germans than any other nationality in 1939 and continued to admit Germans throughout the war.4646 German nationals were for instance admitted in 1941. Foreign Nationals Entering the UK 1938-1951, HMSO.

In late November 1938 the UK Parliament agreed to allow up to 15,000 unaccompanied children to enter Britain as refugees from the Nazis. Almost 10,000 such children from several European countries, but principally from Germany, were rescued by Britain in what became known as the Kindertransport. The first transport left Germany in December 1938 with most ending at the outbreak of war, but a final Kindertransport left the Netherlands in May 1940.

An ever-increasing number of passengers travelled in happier circumstances on the great liners of the day. The for instance presented problems in quickly clearing large numbers of passengers and to do so within Victorian Customs Sheds was increasingly impractical. Shipping companies invited a solution whereby Immigration Officers travelled 1st class on the liner itself or pre-cleared passengers in Cherbourg. In 1936 air traffic had grown to such an extent that a Chief Immigration Officer was appointed to take charge at Croydon Airport with additional responsibilities for immigration control in the new Gatwick terminal, which with its very own direct rail link to London and art deco architecture was the last word in airport design until it was replaced in the 1950s.

1939–1945: Immigration control during the Second World War War brought with it new emergency powers which meant that the Immigration Service now, as well as continuing to control the entry of a wave of displaced people, had to screen refugees, enforce rules on exit permits for all people leaving the UK and to take on the additional work of repatriating some enemy aliens. Ireland's neutrality meant that steps had to be taken to introduce new controls between the UK and Republic. The Passenger Traffic Order 1939 remained in force until 1952 and a large proportion of the work of the immigration service during the war was taken up by the control of Irish workers seeking employment in the growing war economy.