Former UK Prime Minister Tony Blair has warned voters that time is running out to reverse Brexit.
Mr Blair says the split from Brussels will be regretted for generations to come.
He implored the UK’s Labour Party, led by Jeremy Corbyn, to join the fight to stop Brexit.
Mr Blair warned that Britain would be poorer and weaker after it breaks with Brussels. He pointed out that UK Prime Minister Theresa May has solved none of the problems over Northern Ireland's post-Brexit status.
"We are making an error the contemporary world cannot understand and the generations of the future will not forgive," Mr Blair said in an article published on his website.
"2018 will be the last chance to secure a say on whether the new relationship proposed with Europe is better than the existing one.”
"If Labour continues to go along with Brexit and insists on leaving the Single Market, the handmaiden of Brexit will have been the timidity of Labour."
The split from Europe will be Britain's most significant geopolitical move since the Second World War.
A poll published in December 2017 showed that half of Britons support a second vote on whether to leave the European Union and a majority think the government may be paying too much money to the EU to open the way to trade talks.