No, not to safeguard this, that or the other.
Nor for any Red Lines.
His real motive was to avoid a REFERENDUM on the update of the EU Treaty, which would then be necessary, and which the British Eurosceptics would surely win, spawning a much stronger popular pressure for leaving the EU altogether.
Maastricht Treaty
The Treaty of Brussels.
The Treaty of the European Union, or the Maastricht Treaty
The Treaty of Maastricht
They are a member of the EU and the Schengen Treaty.
The Treaty on the European Union or the Maastricht Treaty
The Lisbon Treaty.
The Maastricht Treaty.
Not with the whole EU but only with some of the EU Member States.
The Lisbon Treaty.
The former came into being by the Treaty of Rome 1957 and the latter by the Treaty on European Union of 1992 but the Treaty of Lisbon of 2007 (ratified in 2009) amended those two treaties to make the EC (renamed TFEU, Treaty on the Functioning of the EU) as one of the three pillars of the EU.
No treaty, but a referendum on whether or not to join the EEC was held in the UK.