EU leaders hope that the Lisbon Treaty will come into force as early as November after Ireland agreed today to re-run the referendum that rejected the controversial document a year ago.

Irish voters will be asked to try again in early October after a series of legal guarantees stating that the treaty will not change Ireland's taxation, abortion laws or military neutrality were agreed by the 27 EU leaders at their summit in Brussels.

If - as polls suggest – they pass the treaty, it will pave the way for a new post of President of the European Council, for which Tony Blair is understood to be a leading candidate. He could be appointed by EU leaders as soon as their next summit in October.

Brian Cowen, the Taoiseach, won assurances that the guarantees would be added to the next EU treaty - likely to be the accession of Croatia in 2010 or 2011 - despite British and Czech fears that this could allow MPs another chance to block the Lisbon Treaty, or open up debate on their country's relationship to the EU.

Lawyers from the British government worked through the night to draft a decision that would meet Mr Cowen's demands without opening a Pandora's Box for eurosceptics.

The EU leaders declared: "The protocol will in no way alter the relationship between the EU and its member states. The protocol will clarify but not change either the content of the application of the Treaty of Lisbon."

However Vaclav Klaus, the eurosceptic Czech President who has likened the EU to Communism, vowed to bring the treaty back to the country's parliament soon if he could for a fresh debate.

Czech MPs passed the treaty earlier this year but it is still awaiting Mr Klaus' signature. He refused to sign to avoid putting extra pressure on Irish voters.

The Lisbon Treaty has been controversial because it was created from the ashes of the failed EU Constitution and contained almost all of the measures it envisaged before being rejected by voters in France and Holland in 2005.

Tony Blair promised a referendum on the EU Constitution but the government refused to call one on Lisbon, arguing that it was a regular treaty and not a constitutional document. The treaty will end the national veto over 50 extra policy areas to "streamline" decision-making by qualified-majority voting.

Mr Cowen, who is expected to announce the firm date for the second referendum on Monday, said: "Together we have agreed a package of legally-binding guarantees that respond positively and decisively to the concerns of the Irish people. Doubts raised about certain issues have been clarified and put to rest once and for all.

"The EU is the means by which we make a meaningful impact on the wider wold in which we exist. The Lisbon Treaty will equip the EU to deal with an unpredictable future. And more than ever we need an effective Europe now."

He added: "I am confident we now have a solid basis to go the Irish people and ask them again for their approval for Ireland to ratify the treaty so Europe can move on."

Jose Manuel Barroso, the European Commission president, said: "I'm especially pleased that we have agreed the Irish guarantees. This gives the Irish people all the guarantees they need. It gives me all confidence we will get a Yes vote at the Irish referendum."

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