A "real change in clarity" regarding Brexit could cause a rare rally for both sterling and U.K. stocks, one strategist told CNBC Tuesday.
British Members of Parliament are set to vote on Tuesday whether to accept or reject Prime Minister Theresa May's revised Brexit deal, ahead of the U.K.'s scheduled March 29 departure from the EU.
Speaking to CNBC's "Squawk Box Europe" Tuesday, Willem Sels, chief market strategist at HSBC Private Bank, said the outcome of the vote could spark a rally across U.K. assets.
"Very rarely do we have the equity market and the currency moving together, but there are those days when there's real change and risk appetite," he said.
"People have not had the confidence to go into U.K. assets, our clients do not want to stick their neck out at this point in time. But if there was a real change in clarity then you could have the two moving together upward — (a Brexit deal) could do the trick."