(CNN) As US President Donald Trump and Russian President Vladimir Putin prepare to meet in Helsinki, Finland in two weeks, a former top UK government official said their summit could further strain the United States' relationship with its Western allies.

"It makes the US a less reliable partner for Western countries like my own," former UK Chancellor of the Exchequer George Osborne told CNN's Fareed Zakaria on Sunday.

Osborne, now the editor of the Evening Standard, appeared on "Fareed Zakaria GPS" with Alistair Campbell, Tony Blair's ex press maven, where the two men weighed in on the relationship between the US and Russia and what it means for the Western alliance.

Zakaria noted that the location of the Trump-Putin meeting is "an interesting choice," given that the historic Helsinki Accords was signed there. That 1975 agreement was reached by the United States, Canada, and almost every European country to solidify the post-World War II order in Europe and reduce tensions between the Western and Soviet blocs.

"Of course, the atmospherics drives the media agenda, all of which points to a sort of disintegration of Western unity," Osborne said.

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