Sterling lost more than half a percent against the euro today, with the single currency up broadly as worries over North Korea drove a flight from riskier assets.
Domestic political uncertainty also kept the battered pound under pressure.
Data showing growth in Britain's construction sector hit a one-year low in August - hurt by an investment slump in the commercial sector as Brexit uncertainty weighed - had little measurable effect on the currency.
Analysts said data tomorrow from the dominant services sector would be more important.
Numbers on Friday showed speculators added to their bets against the pound in the week up to last Tuesday, on the back of weak economic data as well as uncertainty about Britain's departure from the European Union.
Prime Minister Theresa May warned lawmakers over the weekend that Britain could be faced with a Brexit "cliff edge" if they failed to back her EU repeal bill, which is to be debated in parliament on Thursday.
May failed to win a clear mandate at a snap election in June and only has a slim majority in parliament that rests on an agreement with the Democratic Unionist Party.
She remains vulnerable if pro-European lawmakers in her Conservative party team up with other parties to vote down legislation or support amendments.
Finance minister Philip Hammond urged lawmakers not to seek to delay the legislation.
On Saturday, May's deputy advised Conservative lawmakersagainst doing anything that would increase Labour's chances ofreturning to power, while May said the bill was the best way toensure a successful Brexit.
Against the dollar, sterling slipped 0.2% to $1.2917.
It was down 0.7% against the euro at 92.23 pence, with traders cautious following Sunday's news of North Korea's sixth and most powerful nuclear test, which prompted the United States to warn of a "massive" military response if it or its allies were threatened.