Gordon Brown has said for the first time that he is unlikely to call a referendum on a new EU treaty, provided Britain’s so-called “red line” issues were not crossed.

Speaking on the BBC’s special Meet the Editors programme, he reasserted the government position that the new treaty would be an amending document and not a new constitution.

He said: “This is no longer a new constitution; it’s an amending treaty rather similar to Amsterdam, Nice, rather than being a new constitution. Now let’s see what comes out of it.”

Earlier on Radio 4’s The World at One, shadow foreign secretary William Hague claimed that “the government’s only objective is to avoid having a referendum in Britain.”

He reiterated the Conservative calls for a referendum, citing the government’s pledge to hold a poll on any document that transferred more power from Britain to the European Union and reacted to reports of the progress of negotiations.

Hague said: “It seems unlikely that agreement will be reached on anything that doesn’t transfer more power from Britain to the EU and the government committed to a referendum.”

Austin Mitchell MP, a veteran Labour Eurosceptic, said that the government had “missed a trick” by virtually ruling out a referendum before the summit meeting on the treaty, thus weakening their negotiating position.