A strategist warned that ongoing sell-offs in equity markets are drawing slight parallels with the crash of the late 1980s. Simon Derrick, chief currency strategist at BNY Mellon, raised concerns Monday around recent market moves. "Without wishing to be too alarmist, there have been a few parallels to what was happening 30 years ago in terms of what's been happening to the dollar, what's been happening to oil prices, what's been happening to Treasury yields," he told CNBC's "Squawk Box Europe." "It's all very September/October 1987 from that perspective." Derrick referred to the volatile market, dubbed "Black Monday," that began on October 19, 1987, in Asia before spreading to Europe and then the United States later in the day. The Dow Jones industrial average fell more than 500 points — or 22 percent — in a single day. Last week, major markets fell deep into the red with fears of an escalating trade war between the U.S. and China. Higher Treasury yields — effectively the cost of borrowing in the U.S. — also unnerved investors, as well as political problems in Italy and worries over Brexit negotiations in the U.K. Derrick was adamant that current events wouldn't play out like they did 1987, but said a "confluence of different circumstances" could lead to a serious risk-off event, leading the market to get significantly worse this week. "Could it get significantly worse (this week)? Yes," he said.

Traders work on the floor of the New York Stock Exchange. Michael Nagle | Bloomberg | Getty Images

Sterling hangs in the balance

One of those circumstances was a no-deal Brexit, Derrick explained, as negotiations between the U.K. and the EU continue to influence sterling's value and investor confidence. The U.K. leaves the bloc on March 29, by which time an agreement will have to be negotiated with the EU and voted through by the country's parliament to avoid a no-deal Brexit. Parliament's vote, according to Derrick, is where sterling's value truly hangs in the balance. "Ironically, from the perspective of those that were looking for the possibility of a second referendum, no deal coming back might be the best thing because the likelihood of that being voted through parliament is incredibly low," he said. "So the reaction of sterling only coming off modestly — we're still in the 1.30s against the dollar — is probably the right thing, it's not at this point that you're going to see the reaction, it's whatever parliament decides ultimately that's going to be the determinant in this. "The danger is that, in all of this, if we come back and there's no deal, that actually we end up in stasis, we end up in gridlock in parliament and actually the default is that we end up in the end of March with Article 50 being triggered with no deal, that's the worst case."

A second referendum?