The former Labour leader, and ex-Lib Dem head Nick Clegg, have formed common ground with the SNP, the Greens, and some Tories to seek a strong voice for the Commons in the Brexit process.
The grouping believes that while Britain narrowly voted to leave the EU, it did not vote to leave the single market.
Mr Miliband said that parliament must remain sovereign.
“Having claimed that the referendum was about returning sovereignty to Britain, it would be a complete outrage if May were to determine the terms of Brexit without a mandate from parliament.
“There is no mandate for hard Brexit, and I don’t believe there is a majority in parliament for it either. Given the importance of these decisions for the UK economy … it has to be a matter for MPs,” he told the Observer.
Article source: http://www.huffingtonpost.co.uk/2016/10/09/ed-miliband-brexit-theresa-may_n_12418070.html?utm_hp_ref=uk-politics&ir=UK+Politics