Gordon Brown has set aside up to three months to ratify the new EU reform treaty after it was agreed by European leaders last night, raising the spectre of the tumultuous parliamentary battles over Maastricht 15 years ago.

The Prime Minister briefed his Cabinet colleagues on Tuesday to expect another protracted tussle on the latest treaty, starting in the new year and continuing well into the spring, The Times has learnt.

He told them that months of detailed examination will dampen Eurosceptics’ opposition while demonstrating that the document is too complex to be decided by referendum.

Ministers also hope to revive voters’ memories of a divided and weak Conservative Party under John Major, obsessed with every detail of the European Union. The 14-month debate over the Treaty of Maastricht, which transferred some powers from Westminster to Brussels, split the Tories.

The reform treaty was agreed by leaders of the 27 EU nations after talks that stretched through their summit dinner.

Mr Brown confounded those expecting a reprise of his previous role as a reluctant European when he arrived in Lisbon yesterday for his first EU summit as Prime Minister. Instead he urged recalcitrant leaders to accept the final version of the EU reform treaty.

Mr Brown scheduled face-to-face meetings in the margins of the summit with both Romano Prodi, his Italian counterpart, and Lech Kaczynski, the Polish President. They were seen as the two biggest stumbling blocks to agreement, with the Italians demanding extra MEPs and the Poles’ insisting on greater voting powers for medium-sized countries. Officials last night confirmed a deal to resolve their concerns.

In his first meeting with Mr Prodi since entering No 10, Mr Brown urged the Italian leader to agree the treaty so that the process of ratification could begin. The Prime Minister also joined in the armtwisting of the Polish President, who threatened as he arrived in the Portuguese capital to delay the treaty if he did not get what he wanted.

Last night, after agreement was reached, Mr Brown insisted the British national interest had been protected. “It is now time for Europe to move on and devote all our attentions to the issues that matter to the people of Europe — economic growth, jobs, climate change and security,” he said.

Speaking before the start of formal talks on the document, Mr Brown effectively destroyed any remaining hopes that it could be put to a referendum, insisting that it did not represent “fundamental change”.

“Let’s now have the debate in the country,” he said. “That will be reflected in a very substantial number of days in the Houses of Parliament and people can judge for themselves whether the British national interest has been protected.”

Although Geoff Hoon, the Chief Whip, has yet to finalise the number of days allocated in the House of Commons, Labour MPs were told this week to expect significantly more than 20. It is understood that legislation will be introduced after Christmas and a target of late March has been set for completing the passage of the Bill ratifying the treaty.

Times Recommends

• Please help: maimed children of war want their lives back
• Cabal seizes diamond riches to buy power
• White House gatecrashers got to the president