BBC: Pressure is growing on the UK government to ratify the Paris climate change deal immediately.
A spokesman for the prime minister told the BBC the UK would ratify "as soon as possible", but did not suggest a date.
But Labour, the Lib Dems, SNP and the Greens say the UK has lost its long-term leadership on climate after the US and China jointly ratified the deal at the weekend.
They say there is no good reason for the UK to delay.
Labour warns that unless ministers start the ratification...