It will be a long Sunday night for currency traders at Barclays Plc.

The bank will have traders and salespeople at their desks in London and New York, starting at about 7 p.m. British time, as the global foreign-exchange market begins trading in New Zealand, according to a Barclays spokeswoman.

On Saturday, Oct. 20, Prime Minister Boris Johnson will either win or lose a vote in the House of Commons on the Brexit deal he reached with the European Union -- and most likely, as a result of that vote, the pound will be on the move at the earliest possible moment, just as it was in the wild night of trading that followed referendum day in 2016.

Barclays didn’t specify how many staff will be involved. While the bank has traders based in Asia-Pacific time zones, it wants more hands on deck given the prospect of unusual volatility. With much of the usual pound-trading market asleep, liquidity could be low, and the risk of so-called flash moves is elevated.

Barclays research, sales and trading staff will also host a call on Sunday afternoon for clients, the spokeswoman said.

None other than Mark Carney is predicting there will be action in the market. “This process is going to break one way or the other, and the pound is going to move either up or down,” the governor of the Bank of England said on Oct. 15. “There’s great investment advice,” he quipped.

Johnson is battling to sell his deal to skeptical British parliamentarians who repeatedly kiboshed the previous withdrawal agreement reached by his predecessor, Theresa May. Since Oct. 9, optimism that Britain would avoid a no-deal Brexit on the Oct. 31 deadline has sent sterling surging from $1.22 to about $1.29.

If Johnson fails to convince enough lawmakers from his Conservative party and the opposition, he will face the choice of seeking to delay Brexit again or trying to take the country out of the bloc without a deal.