Germany’s main political parties have reached a deal on a law that will enable Berlin to ratify the EU’s Lisbon treaty.

The legislation was tweaked to comply with the constitution, giving the German parliament more say at European level. However, some politicians have demanded bigger changes which could delay ratification until after national elections next month. Along with Germany — Ireland, Poland and the Czech Republic are the only other EU states yet to adopt the treaty, which aims to streamline EU decision making. Irish voters rejected it last year but are due to take part in a second referendum this October. All 27 member states must approve Lisbon for it to take effect and any delay could be embarrassing for Chancellor Angela Merkel who’s spearheaded efforts to ratify the treaty.