Gordon Brown has signed the controversial European reform treaty.

The prime minister missed the official session and signed the document in Lisbon a few hours after other EU leaders.

The Council meeting formally agreed the text of the treaty at a signing session which took place at lunchtime in the Portuguese capital.

However, the prime minister was absent from this part of the event due to his appearance before the Commons liaison committee in Westminster on Thursday morning.

In his absence, foreign secretary David Miliband represented Britain at the ceremony, although his own attendance was earlier put in doubt when his flight was delayed for two hours.

Brown has ruled out a referendum on the treaty, but he told the liaison committee there would be "more scope for Parliament to debate some of these issues than there has been in the past".

He said that some of the changes "are minor and procedural and the other ones are in Britain's interest". 

"If they are not we have usually got an opt-in or an opt-out to decide whether we wish to be part of it," the prime minister added.

With the signing now out the way, Britain was keen for the summit which continues in Brussels on Friday to turn its attention to what Downing Street called "substantive issues".

The prime minister's spokesman said the negotiations over the treaty had been an "introspective period" for the EU as it concentrated on its own internal arrangements.

The UK is keen for Europe to concentrate on how its economies respond to globalisation and its place in the world.

"For the foreseeable future that the focus of Europe is now on economics, security, trade, economic reform, climate change and not on institutional debate," Brown told Thursday's Times newspaper.

"The global agenda would then force Europe to look a internal economic reform, the liberalisation of utilities, finance, energies in a consistent way so you genuinely can talk about open markets and trading."

The summit was also set to discuss Kosovo after the for discussions on its future status expired on Monday.