Russian oil revenues hit a nine-month peak last month as rising prices have “smashed” the G7 cap aimed at hitting Moscow’s war chest, according to the International Energy Agency (IEA).

The IEA said on Friday that the largest crude export grade, Urals, had breached the cap “making all Russian [crude] oil exports ineligible for G7 and EU maritime services”.

The declaration is significant as the body calculates the weighted average of Russian seaborne exports that is considered by the G7 group of nations in their bi-monthly review of the price cap’s effectiveness.