Britain's Secretary of State for International Trade Liam Fox arrives in Downing Street, London, Britain, November 13, 2018. REUTERS/Peter Nicholls

LONDON (Reuters) - British Trade Secretary Liam Fox said on Tuesday a lot of effort was being put into achieving a Brexit deal with the European Union as no one believed leaving without an agreement was a good outcome.

During a question and answer session following a speech in London, Fox, a strong Brexit supporter, said it was impossible to know whether he would like the final deal, which both sides say has almost been agreed, until he knew what it was.

“Over the last few days in particular, there has been a lot of effort put in to get to an agreement on the withdrawal agreement itself and I think all you can say is that there is a lot of effort being put into reaching that because none of us believes that no deal is a good outcome,” he said.

With less than five months until Britain is due to leave the EU, talks are mired in a disagreement over an Irish “backstop” - an insurance policy to ensure there will be no hard border between British-ruled Northern Ireland and EU member Ireland - if a future trading relationship is not in place in time.

Local media have reported Fox is among key pro-Brexit ministers who are concerned Britain could end up locked into a customs union with the EU.

“I will want to look at the package as a whole,” Fox said when asked at what point he might consider a deal so bad that it would be worse than leaving without a deal.

“We need to look at any agreement in the round and we need to make a judgment about is that in the best interests of the United Kingdom and we have to weigh it against the alternatives.”

For Britain to be “perpetually” in a customs union would be “a profound impediment to an independent trade policy”, he said.