Officials and diplomats in Brussels are growing increasingly pessimistic about the chances of enforcing a full ban on maritime services for Russian tankers, as both internal and external factors weigh against the ambitious proposal.

"It's not happening," a diplomat bluntly said.

The ban was approved in late April as part of the 20th package of sanctions to cripple Moscow's war economy. It is designed to prohibit all maritime-related services, including banking, shipping, flagging and insurance, for tankers carrying Russian oil.

Crucially, the far-reaching measure was left on hold sine die.

The official reason for the pause was a desire to reach an agreement at the G7 level following the example of the price cap, which was adopted in conjunction with allies.