A British and a European flag are pictured ahead of the European Union leaders summit in Brussels, Belgium October 17, 2018. REUTERS/Yves Herman

LONDON (Reuters) - Britain is working to secure a Brexit deal as soon as possible, Prime Minister Theresa May’s spokesman said on Monday, adding that a decision on whether to hold a special Brexit summit later this month is up to the European Union.

Earlier ITV’s political editor reported that the British government had decided that unless a deal was struck within a week, the default option of a no-deal Brexit becomes the probable outcome.

Asked about reports that this week was a decisive one in the Brexit negotiations, May’s spokesman said: “We are working to secure a deal as soon as possible, in relation to that particular summit, the European Council set out its position at the EU Council in October. It’s obviously a decision for them.”

On the main sticking point in the negotiations, a backstop to maintain an open border between the British province of Northern Ireland and EU member Ireland, the spokesman said: “We don’t want the backstop to be in place indefinitely and (we have said) that we would be looking to a mechanism to achieve that.”