By the Treaty of Paris of 5th November 1815, the Ionian Islands were declared 'one and only free state, protected directly and exclusively by His Majesty, the King of the United Kingdom'. The declaration and appointment of an English Commissioner demonstrated the protectorate regime of the 'United State of Ionian Islands'.

The Ionian forts, occupied by the English, were signs of this subjection, along with the need to ratify the Constitution on the part of the 'Protective Power' and the one-dimensional political relations between the state of the Ionians and the United Kingdom. In the Ionian Islands there were consuls of other states, including Greeks, but no diplomats chargés d'affaires, consuls, etc. And the 'United State' could not even appoint such representatives in third states, leaving its external policy in the hands of England. Moreover, it had to provide for the British political and military personnel on the islands, offering a superfluous allowance to the Royal Funds.

Of course the Ionian Islands state kept its special institutions, such as the Constitution, as well as national symbols such as the flag. This flag was recognised as a 'merchant flag' too, even though this legal right could practically be abolished, as was the case in the Crimean War when two merchant ships from the Ionian Islands were caught by English ones as they were travelling to Taygan, in the Sea of Azov, for trading purposes. Despite the legal justifications of the Ionian Islands, in practice the institutions functioned only when benefiting the more powerful.

However, the Ionian Islands state was the first 'Hellenic' state to be founded, albeit under English rule, to establish some institutions and to acquire political experience, which was later absent for years from the Greek kingdom. The first Constitution of 1817 granted a lot of authority to the Commissioner. In spite of the existence of a Parliament, the need for a more free regime was obvious, even in England.

In 1843, John Colborne was installed in Corfu as Commissioner, initiating a period of reforms, including the permission for the operation of political clubs, the foundation of private printing houses and the introduction of Greek newspapers.
Press limitations were cancelled and the first political newspaper was issued in 1848: To Mellon in Zakynthos, Patris in Corfu, Philelephtheros, Anagennisis and Enosis in Kefallonia. At the same time, the political institutions' dependence on the High Commissioner - especially on the part of the Senate - was reduced. In 1848, amid the storm of European revolutions, rebellions broke out in Kefallonia, which was violently oppressed by the regime.

The press played an important role in the disclosure of the arbitrariness and acts of violence of the English police. In the Ionian Islands, political thinking on the rights of the citizen and his protection from authority, as well as on the principles of a democratic state, with the dogmas of popular sovereignty and the triptych of the French Revolution (equality, fraternity, freedom), developed relatively early.

The main problem for the Ionian Islands was subjection to the English crown. Parties were named after their position on that issue: Prostasianoi (Protection Supporters), Reformers and Radicals. The ninth Parliament of the 'United State', at which the Radicals and Reformers prevailed, proceeded to revolutionary decisions. It established 25th March as a national holiday, tried to secure by legislation citizens' personal freedoms and established Greek as the only official language of the state.
The Radical party did not consider any reformative movement to be effective; besides, the Commissioner and Senate cancelled them. The Radicals proposed that the only solution was Union with Greece. On 25th October 1850, radical members of the Parliament proposed an act which declared the Ionian Islands people's wish to be united with Greece and free themselves from English 'protection'. The Commissioner interrupted Parliament's operation and on 10th December declared its dissolution. Many radical leaders were expelled or exiled. The following elections were completed in an atmosphere of excessive violence and fraud.
At the next Parliament, the Commissioner tried to dictate conservative reforms and press limitations, but failed. In the next years, the conflict on the issue of protection and Union was intensified. The arrival of William Ewart Gladstone in 1858 was an opportunity for many demonstrations to be made in favour of the Union and against the English protection.
The enactment on 15th-27th January by the Parliament declared the 'only and unanimous wish of the entire Ionian peoples [for the] Union of all the Ionian Islands with the Kingdom of Greece'. Gladstone's admonition for a 'pleading presentation' before the Queen caused a rift in the radical classes that supported the Union. The purest ideologists of the movement demanded a Union based on the nations' principles and on the respect of public will, not one offered as a gift by the Queen.

The twelfth Parliament declared as president and vice-president two former exiled men, Zervos and Momferatos, thus honouring the people who were in favour of the Union. The Parliament strongly supported the Union which was finally declared in 1863, at the thirteenth Parliament, following the Commissioner's order. The radicals' position on the unconditional Union with Greece was forgotten in the general euphoria over the final result.