The pound tumbled to its lowest level in three decades amid mounting concern the U.K. is heading for a so-called hard Brexit that would restrict access to the European Union's single market.

Sterling exceeded its lows versus the dollar set in the wake of the June 23 referendum and touched the weakest in 3½ years against the euro. The slide extended as Prime Minister Theresa May was said to take the view that financial services would get no special favors in EU exit talks. The pound has fallen against all 16 of its major peers since the premier's weekend announcement that she'll trigger the formal process for quitting by March.

“We have the market facing the reality that Brexit is about to begin and we could be faced with hard Brexit,” said Jane Foley, a senior currency strategist at Rabobank International in London. The reports about the financial sector are “just lacing the concerns the market already has about the outlook for growth, investment and jobs in the U.K. economy.”