London (CNN) A senior UK government minister has warned there is a "50-50" chance Brexit won't happen, if Prime Minister Theresa May's deal is voted down in Parliament next month.

International Trade Secretary Liam Fox, a prominent Brexit supporter, told the Sunday Times that the only way to be "100% certain" Britain will leave the European Union is if ministers back the deal.

The UK is scheduled to exit the bloc on March 29 next year. But the road to departure has been a bumpy one -- with the latest hurdle May's beleaguered withdrawal agreement, negotiated with the EU last month.

Liam Fox was a prominent supporter of Brexit in the runup to the 2016 referendum.

The deal needs the backing of UK ministers to go ahead, and a vote was due to be held earlier this month.

But just hours before the vote was to happen, May pulled the plug when it became clear she would lose "by a significant margin."